This revision was not accepted when it landed; it landed in state "Needs
Review".
This revision was automatically updated to reflect the committed changes.
Closed by commit rG3dcfd482cb17: [CodeGen] Increase applicability of
ffine-grained-bitfield-accesses for targets… (authored by asb).
Changed prior to commit:
https://reviews.llvm.org/D79155?vs=261138&id=270344#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D79155/new/
https://reviews.llvm.org/D79155
Files:
clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
clang/test/CodeGenCXX/finegrain-bitfield-type.cpp
Index: clang/test/CodeGenCXX/finegrain-bitfield-type.cpp
===================================================================
--- clang/test/CodeGenCXX/finegrain-bitfield-type.cpp
+++ clang/test/CodeGenCXX/finegrain-bitfield-type.cpp
@@ -1,5 +1,12 @@
// RUN: %clang_cc1 -triple x86_64-linux-gnu -ffine-grained-bitfield-accesses \
// RUN: -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple riscv64-linux-gnu -ffine-grained-bitfield-accesses \
+// RUN: -emit-llvm -o - %s | FileCheck %s
+
+// Note: This test checks the X86-64 and RISC-V targets in order to explore
+// behaviour when i8/i16 are native integer widths (X86-64) and when they're
+// not (RISC-V).
+
struct S4 {
unsigned long f1:28;
unsigned long f2:4;
@@ -19,4 +26,4 @@
// CHECK: %struct.S4 = type { i32, i16 }
// CHECK-NOT: %struct.S4 = type { i48 }
// CHECK: %struct.S5 = type { i32, i32, i16, [6 x i8] }
-// CHECK-NOT: %struct.S5 = type { i80 }
\ No newline at end of file
+// CHECK-NOT: %struct.S5 = type { i80 }
Index: clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
===================================================================
--- clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -406,15 +406,17 @@
return;
}
- // Check if OffsetInRecord is better as a single field run. When
OffsetInRecord
- // has legal integer width, and its bitfield offset is naturally aligned, it
- // is better to make the bitfield a separate storage component so as it can
be
- // accessed directly with lower cost.
+ // Check if OffsetInRecord (the size in bits of the current run) is better
+ // as a single field run. When OffsetInRecord has legal integer width, and
+ // its bitfield offset is naturally aligned, it is better to make the
+ // bitfield a separate storage component so as it can be accessed directly
+ // with lower cost.
auto IsBetterAsSingleFieldRun = [&](uint64_t OffsetInRecord,
uint64_t StartBitOffset) {
if (!Types.getCodeGenOpts().FineGrainedBitfieldAccesses)
return false;
- if (!DataLayout.isLegalInteger(OffsetInRecord))
+ if (OffsetInRecord < 8 || !llvm::isPowerOf2_64(OffsetInRecord) ||
+ !DataLayout.fitsInLegalInteger(OffsetInRecord))
return false;
// Make sure StartBitOffset is natually aligned if it is treated as an
// IType integer.
Index: clang/test/CodeGenCXX/finegrain-bitfield-type.cpp
===================================================================
--- clang/test/CodeGenCXX/finegrain-bitfield-type.cpp
+++ clang/test/CodeGenCXX/finegrain-bitfield-type.cpp
@@ -1,5 +1,12 @@
// RUN: %clang_cc1 -triple x86_64-linux-gnu -ffine-grained-bitfield-accesses \
// RUN: -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple riscv64-linux-gnu -ffine-grained-bitfield-accesses \
+// RUN: -emit-llvm -o - %s | FileCheck %s
+
+// Note: This test checks the X86-64 and RISC-V targets in order to explore
+// behaviour when i8/i16 are native integer widths (X86-64) and when they're
+// not (RISC-V).
+
struct S4 {
unsigned long f1:28;
unsigned long f2:4;
@@ -19,4 +26,4 @@
// CHECK: %struct.S4 = type { i32, i16 }
// CHECK-NOT: %struct.S4 = type { i48 }
// CHECK: %struct.S5 = type { i32, i32, i16, [6 x i8] }
-// CHECK-NOT: %struct.S5 = type { i80 }
\ No newline at end of file
+// CHECK-NOT: %struct.S5 = type { i80 }
Index: clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
===================================================================
--- clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -406,15 +406,17 @@
return;
}
- // Check if OffsetInRecord is better as a single field run. When OffsetInRecord
- // has legal integer width, and its bitfield offset is naturally aligned, it
- // is better to make the bitfield a separate storage component so as it can be
- // accessed directly with lower cost.
+ // Check if OffsetInRecord (the size in bits of the current run) is better
+ // as a single field run. When OffsetInRecord has legal integer width, and
+ // its bitfield offset is naturally aligned, it is better to make the
+ // bitfield a separate storage component so as it can be accessed directly
+ // with lower cost.
auto IsBetterAsSingleFieldRun = [&](uint64_t OffsetInRecord,
uint64_t StartBitOffset) {
if (!Types.getCodeGenOpts().FineGrainedBitfieldAccesses)
return false;
- if (!DataLayout.isLegalInteger(OffsetInRecord))
+ if (OffsetInRecord < 8 || !llvm::isPowerOf2_64(OffsetInRecord) ||
+ !DataLayout.fitsInLegalInteger(OffsetInRecord))
return false;
// Make sure StartBitOffset is natually aligned if it is treated as an
// IType integer.
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