Hi, The patch enables have_cbrnachcc4 which is a flag in ifcvt.cc to indicate if branch by CC bits is invalid or not. The new expand pattern "cbranchcc4" is created which intend to match the pattern defined in "*cbranch", "*cbranch_2insn" and "*creturn". The operand sequence in "cbranchcc4" is inline with the definition in gccint. And the operand sequence doesn't matter in pattern matching. So I think it should work.
Compared to last version, one new predicate and one new expander are created. Bootstrapped and tested on powerpc64-linux BE and LE with no regressions. Is this okay for trunk? Any recommendations? Thanks a lot. ChangeLog 2022-11-17 Haochen Gui <guih...@linux.ibm.com> gcc/ * config/rs6000/predicates.md (all_branch_comparison_operator): New, and includes operators in branch_comparison_operator and extra_insn_branch_comparison_operator. * config/rs6000/rs6000.md (cbranchcc4): New expand pattern. gcc/testsuite/ * gcc.target/powerpc/cbranchcc4.c: New. patch.diff diff --git a/gcc/config/rs6000/predicates.md b/gcc/config/rs6000/predicates.md index b1fcc69bb60..843b6f39b84 100644 --- a/gcc/config/rs6000/predicates.md +++ b/gcc/config/rs6000/predicates.md @@ -1308,6 +1308,7 @@ (define_special_predicate "equality_operator" ;; Return 1 if OP is a comparison operation that is valid for a branch ;; instruction. We check the opcode against the mode of the CC value. + ;; validate_condition_mode is an assertion. (define_predicate "branch_comparison_operator" (and (match_operand 0 "comparison_operator") @@ -1331,6 +1332,11 @@ (define_predicate "extra_insn_branch_comparison_operator" GET_MODE (XEXP (op, 0))), 1"))) +;; Return 1 if OP is a comparison operation that is valid for a branch. +(define_predicate "all_branch_comparison_operator" + (ior (match_operand 0 "branch_comparison_operator") + (match_operand 0 "extra_insn_branch_comparison_operator"))) + ;; Return 1 if OP is an unsigned comparison operator. (define_predicate "unsigned_comparison_operator" (match_code "ltu,gtu,leu,geu")) diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md index e9e5cd1e54d..7b7d747a85d 100644 --- a/gcc/config/rs6000/rs6000.md +++ b/gcc/config/rs6000/rs6000.md @@ -13067,6 +13067,16 @@ (define_insn_and_split "*<code><mode>_cc" ;; Conditional branches. ;; These either are a single bc insn, or a bc around a b. +(define_expand "cbranchcc4" + [(set (pc) + (if_then_else (match_operator 0 "all_branch_comparison_operator" + [(match_operand 1 "cc_reg_operand") + (match_operand 2 "zero_constant")]) + (label_ref (match_operand 3)) + (pc)))] + "" + "") + (define_insn "*cbranch" [(set (pc) (if_then_else (match_operator 1 "branch_comparison_operator" diff --git a/gcc/testsuite/gcc.target/powerpc/cbranchcc4.c b/gcc/testsuite/gcc.target/powerpc/cbranchcc4.c new file mode 100644 index 00000000000..528ba1a878d --- /dev/null +++ b/gcc/testsuite/gcc.target/powerpc/cbranchcc4.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-rtl-ce1" } */ +/* { dg-final { scan-rtl-dump "noce_try_store_flag_constants" "ce1" } } */ + +/* The inner branch should be detected by ifcvt then be converted to a setcc + with a plus by noce_try_store_flag_constants. */ + +int test (unsigned int a, unsigned int b) +{ + return (a < b ? 0 : (a > b ? 2 : 1)); +}