[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-08 Thread Rainer Orth via cfe-commits 

rorth wrote:

This patch broke the [Solaris/sparcv9 
buildbot](https://lab.llvm.org/buildbot/#/builders/72/builds/1709): the 
new/changed tests `FAIL` with
```
  File 
/opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/llvm/clang/test/SemaCXX/format-strings-scanf.cpp
 Line 25: _Float16 is not supported on this target
1 error generated.
```

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-07 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong closed 
https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 

Luhaocong wrote:

> Thanks for confirming. Do you need me to merge that for you?

It can't be better, thanks.

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread via cfe-commits 

https://github.com/cor3ntin approved this pull request.

Thanks for confirming.
Do you need me to merge that for you?

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 

Luhaocong wrote:

> LGTM.
> 
> The format diagnostics are new in Clang 18 and as such we do not need a 
> release note. Correct?

This format diagnostics is existent until 
https://github.com/llvm/llvm-project/commit/04e6178ae932c9a1d939dcfe3ef1189f4bbb21aa
 had been committed. Clang 17.0.1 gives a warning: 
https://godbolt.org/z/xMdK9cETY.


https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 


@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}

Luhaocong wrote:

Done

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong updated 
https://github.com/llvm/llvm-project/pull/74439

>From e86dc461c8654b6b9806ad88bf2ba3d731c81d50 Mon Sep 17 00:00:00 2001
From: Lu Haocong 
Date: Tue, 5 Dec 2023 16:45:22 +0800
Subject: [PATCH] [Sema] Warning for _Float16 passed to format specifier '%f'

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
there are no default argument promotions for _FloatN types.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.
---
 clang/lib/AST/FormatString.cpp  |  1 -
 clang/test/Sema/attr-format.c   |  7 +++
 clang/test/SemaCXX/attr-format.cpp  |  1 +
 clang/test/SemaCXX/format-strings-scanf.cpp | 16 ++--
 4 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a24..c5d14b4af7ff15 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78bd..bdfd8425c4e9a5 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776ca..4509c3a95e8efa 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0d..406c2069e28ca7 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;
 float ff;
 double fd;
 long double fl;
@@ -51,18 +52,21 @@ void test(void) {
 // expected-warning@+1{{format specifies type 'int *' but the argument has 
type 'short *'}}
 scan("%hhi %i %li", &b.ss, &b.ss, &b.ss);
 
-// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+// expected-warning@+4{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '_Float16 *'}}
 // expected-warning@+2{{format specifies type 'float *' but the argument 
has type 'double *'}}
 // expected-warning@+1{{format specifies type 'float *' but the argument 
has type 'long double *'}}
-scan("%f %f %f", &b.f16, &b.fd, &b.fl);
+scan("%f %f %f %f", &b.f16, &b.Float16, &b.fd, &b.fl);
 
-// expected-warning@+3{{format specifies typ

[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread via cfe-commits 

https://github.com/cor3ntin approved this pull request.

LGTM.

The format diagnostics are new in Clang 18 and as such we do not need a release 
note. Correct?

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread via cfe-commits 


@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}

cor3ntin wrote:

This test seems unrelated to the change, we should do that in a  separate PR

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread via cfe-commits 

https://github.com/cor3ntin edited 
https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 

Luhaocong wrote:

Thanks for everyone's review. Do you have any other suggestions for this 
change, and can this pull request be accepted ?

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong updated 
https://github.com/llvm/llvm-project/pull/74439

>From 899e18d1ca94efad41c2e09dff0a3213d7fb0f7e Mon Sep 17 00:00:00 2001
From: Lu Haocong 
Date: Tue, 5 Dec 2023 16:45:22 +0800
Subject: [PATCH] [Sema] Warning for _Float16 passed to format specifier '%f'

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
there are no default argument promotions for _FloatN types.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.
---
 clang/lib/AST/FormatString.cpp  |  1 -
 clang/test/AST/variadic-promotion.c |  5 +
 clang/test/Sema/attr-format.c   |  7 +++
 clang/test/SemaCXX/attr-format.cpp  |  1 +
 clang/test/SemaCXX/format-strings-scanf.cpp | 16 ++--
 5 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a24..c5d14b4af7ff15 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/AST/variadic-promotion.c 
b/clang/test/AST/variadic-promotion.c
index 41c7fec8d7943e..7cbadb832ca806 100644
--- a/clang/test/AST/variadic-promotion.c
+++ b/clang/test/AST/variadic-promotion.c
@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78bd..bdfd8425c4e9a5 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776ca..4509c3a95e8efa 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0d..406c2069e28ca7 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;
 float ff;
 double fd;
 long double fl;
@@ -51,18 +52,21 @@ void test(void) {
 // expected-warning@+1{{format specifies type 'int *' but the argument has 
type 'short *'}}
 scan("%hhi %i %li", &b.ss, &b.ss, &b.ss);
 
-// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+/

[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-20 Thread Joshua Cranmer via cfe-commits 

jcranmer-intel wrote:

> [N2844](https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf), as 
> linked by OP, references the removed language that you are looking for.

Doing some more spelunking, no released version of the TS ever had default 
argument promotion. The change to the TS was done shortly before integration in 
C, in response to the C++ proposal for extended floating-point types, but WG14 
objected to the change, so it was dropped in actual integration. See 
https://mailman.oakapple.net/pipermail/cfp-interest/2020-September/001782.html 
for the summary.

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-20 Thread via cfe-commits 

apple-fcloutier wrote:

[N2844](https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf), as linked 
by OP, references the removed language that you are looking for.

As Aaron said, it doesn't matter if clang never claimed conformance/never 
implemented default argument promotion for these types in the first place.

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-20 Thread Joshua Cranmer via cfe-commits 

jcranmer-intel wrote:

> Should this only apply in C23 mode? Standard behavior until C23 is that 
> `_Float16` promotes to `double`. What about C++?

I can't find any reference in older versions of C or TS 18661-3 that suggests 
that `_Float16` is promoted to `double`. The wording of 6.5.2.2 used to say

> If the expression that denotes the called function has a type that does not 
> include a prototype, the integer promotions are performed on each argument, 
> and arguments that have type `float` are promoted to `double`. These are 
> called the default argument promotions.

Which suggests that *only* `float` is promoted and that other floating point 
types are not promoted, and nothing in TS 18661-3 can be construed to suggest 
promotion either (notably, `_Float32` *doesn't* promote to `double`, even 
though it's likely the same representation as `float`!).

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-06 Thread Aaron Ballman via cfe-commits 

AaronBallman wrote:

> Should this only apply in C23 mode? Standard behavior until C23 is that 
> `_Float16` promotes to `double`. What about C++?

`_Float16` wasn't standardized until C23; before then it was part of TS 18661, 
but we never claimed conformance to that (that I'm aware of), so I think we 
have the wiggle room to be consistent across language modes. My bigger question 
is: do we codegen properly and what do C standard libraries expect? e.g., if we 
codegen such that we don't promote in older language modes, will this cause 
problems for runtime libraries?

CC @jcranmer-intel for additional opinions

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-06 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong updated 
https://github.com/llvm/llvm-project/pull/74439

>From 47ec17023ebc75a61951930b77e08bb2f726775b Mon Sep 17 00:00:00 2001
From: Lu Haocong 
Date: Tue, 5 Dec 2023 16:45:22 +0800
Subject: [PATCH] [Sema] Warning for _Float16 passed to format specifier '%f'

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
default argument promotions for _FloatN types has been removed.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.
---
 clang/lib/AST/FormatString.cpp  |  1 -
 clang/test/AST/variadic-promotion.c |  5 +
 clang/test/Sema/attr-format.c   |  7 +++
 clang/test/SemaCXX/attr-format.cpp  |  1 +
 clang/test/SemaCXX/format-strings-scanf.cpp | 16 ++--
 5 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a2..c5d14b4af7ff1 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/AST/variadic-promotion.c 
b/clang/test/AST/variadic-promotion.c
index 41c7fec8d7943..7cbadb832ca80 100644
--- a/clang/test/AST/variadic-promotion.c
+++ b/clang/test/AST/variadic-promotion.c
@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78b..bdfd8425c4e9a 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776c..4509c3a95e8ef 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0..406c2069e28ca 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;
 float ff;
 double fd;
 long double fl;
@@ -51,18 +52,21 @@ void test(void) {
 // expected-warning@+1{{format specifies type 'int *' but the argument has 
type 'short *'}}
 scan("%hhi %i %li", &b.ss, &b.ss, &b.ss);
 
-// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+// expe

[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-05 Thread Haocong Lu via cfe-commits 

Luhaocong wrote:

> Should this only apply in C23 mode? Standard behavior until C23 is that 
> `_Float16` promotes to `double`. What about C++?

It seems clang never support default argument promotions for _Float16, as 
described in 
https://github.com/llvm/llvm-project/blob/main/clang/docs/LanguageExtensions.rst#id68
 five years ago. Is there any demand to support this in old C/C++ standard？

And I try case with -std=c99 (https://godbolt.org/z/xqx8e6oh5) and -std=c++11 
(https://godbolt.org/z/Mrn779Tdq) , GCC give a warning at both.

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-05 Thread via cfe-commits 

apple-fcloutier wrote:

Should this only apply in C23 mode? Standard behavior until C23 is that 
`_Float16` promotes to `double`. What about C++?

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-05 Thread Haocong Lu via cfe-commits 

Luhaocong wrote:

This patch improves implement 
https://github.com/llvm/llvm-project/commit/04e6178ae932c9a1d939dcfe3ef1189f4bbb21aa.
 Could you please help me review this patch @apple-fcloutier @AaronBallman 

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-05 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong updated 
https://github.com/llvm/llvm-project/pull/74439

>From afb0d3909cde31cf73e2baf3efd13d584943704f Mon Sep 17 00:00:00 2001
From: Lu Haocong 
Date: Tue, 5 Dec 2023 16:45:22 +0800
Subject: [PATCH] [Sema] Warning for _Float16 passed to format specifier '%f'

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
default argument promotions for _FloatN types has been removed.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.
---
 clang/lib/AST/FormatString.cpp  |  1 -
 clang/test/AST/variadic-promotion.c |  5 +
 clang/test/Sema/attr-format.c   |  7 +++
 clang/test/SemaCXX/attr-format.cpp  |  1 +
 clang/test/SemaCXX/format-strings-scanf.cpp | 16 ++--
 5 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a2..c5d14b4af7ff1 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/AST/variadic-promotion.c 
b/clang/test/AST/variadic-promotion.c
index 41c7fec8d7943..7cbadb832ca80 100644
--- a/clang/test/AST/variadic-promotion.c
+++ b/clang/test/AST/variadic-promotion.c
@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78b..bdfd8425c4e9a 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776c..4509c3a95e8ef 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0..406c2069e28ca 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;
 float ff;
 double fd;
 long double fl;
@@ -51,18 +52,21 @@ void test(void) {
 // expected-warning@+1{{format specifies type 'int *' but the argument has 
type 'short *'}}
 scan("%hhi %i %li", &b.ss, &b.ss, &b.ss);
 
-// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+// expe

[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-05 Thread via cfe-commits 

llvmbot wrote:




@llvm/pr-subscribers-clang

Author: Haocong Lu (Luhaocong)


Changes

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf, 
default argument promotions for _FloatN types has been removed.

A warning is needed to notice user to promote _Float16 to double explicitly, 
and then pass it to format specifier '%f', which is consistent with GCC.

Fixes: https://github.com/llvm/llvm-project/issues/68538

---
Full diff: https://github.com/llvm/llvm-project/pull/74439.diff


5 Files Affected:

- (modified) clang/lib/AST/FormatString.cpp (-1) 
- (modified) clang/test/AST/variadic-promotion.c (+5) 
- (modified) clang/test/Sema/attr-format.c (+7) 
- (modified) clang/test/SemaCXX/attr-format.cpp (+1) 
- (modified) clang/test/SemaCXX/format-strings-scanf.cpp (+10-6) 


``diff
diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a2..c5d14b4af7ff1 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/AST/variadic-promotion.c 
b/clang/test/AST/variadic-promotion.c
index 41c7fec8d7943..7cbadb832ca80 100644
--- a/clang/test/AST/variadic-promotion.c
+++ b/clang/test/AST/variadic-promotion.c
@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78b..bdfd8425c4e9a 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776c..4509c3a95e8ef 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0..406c2069e28ca 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;
 float ff;
 double fd;
 long double fl;
@@ -51,18 +52,21 @@ void test(void) {
 // expected-warning@+1{{format specifies type 'int *' but the argument has 
type 'short *'}}
 scan("%hhi %i %li", &b.ss, &b.ss, &b.ss);
 
-// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+// expected-warning@+4{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+// expect

[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-05 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong created 
https://github.com/llvm/llvm-project/pull/74439

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf, 
default argument promotions for _FloatN types has been removed.

A warning is needed to notice user to promote _Float16 to double explicitly, 
and then pass it to format specifier '%f', which is consistent with GCC.

Fixes: https://github.com/llvm/llvm-project/issues/68538

>From 10c48f5c8c50617929cc72401721afc379131346 Mon Sep 17 00:00:00 2001
From: Lu Haocong 
Date: Tue, 5 Dec 2023 16:45:22 +0800
Subject: [PATCH] [Sema] Warning for _Float16 passed to format specifier '%f'

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
default argument promotions for _FloatN types has been removed.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.
---
 clang/lib/AST/FormatString.cpp  |  1 -
 clang/test/AST/variadic-promotion.c |  5 +
 clang/test/Sema/attr-format.c   |  7 +++
 clang/test/SemaCXX/attr-format.cpp  |  1 +
 clang/test/SemaCXX/format-strings-scanf.cpp | 16 ++--
 5 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a2..c5d14b4af7ff1 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/AST/variadic-promotion.c 
b/clang/test/AST/variadic-promotion.c
index 41c7fec8d7943..7cbadb832ca80 100644
--- a/clang/test/AST/variadic-promotion.c
+++ b/clang/test/AST/variadic-promotion.c
@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78b..bdfd8425c4e9a 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776c..4509c3a95e8ef 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0..406c2069e28ca 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;