llvm-project/clang/test/CodeGen/const-unordered-compare.c

// RUN: %clang_cc1 -emit-llvm -o - %s | FileCheck %s

// Checks folding of an unordered comparison
int nan_ne_check() {
  // CHECK: ret i32 1
  return (__builtin_nanf("") != __builtin_nanf("")) ? 1 : 0;
}
A not equal for an unordered relation should return true as specified in IEEE-754, e.g., NAN != NAN ? 1 : 0 should return 1. Also fix the case for complex. llvm-svn: 102598 2010-04-29 13:53:29 +08:00			`// RUN: %clang_cc1 -emit-llvm -o - %s \| FileCheck %s`

			`// Checks folding of an unordered comparison`
			`int nan_ne_check() {`
Change IR generation for return (in the simple case) to avoid doing silly load/store nonsense in the epilog. For example, for: int foo(int X) { int A[100]; return A[X]; } we used to generate: %arrayidx = getelementptr inbounds [100 x i32]* %A, i32 0, i64 %idxprom ; <i32> [#uses=1] %tmp1 = load i32 %arrayidx ; <i32> [#uses=1] store i32 %tmp1, i32* %retval %0 = load i32* %retval ; <i32> [#uses=1] ret i32 %0 } which codegen'd to this code: _foo: ## @foo ## BB#0: ## %entry subq $408, %rsp ## imm = 0x198 movl %edi, 400(%rsp) movl 400(%rsp), %edi movslq %edi, %rax movl (%rsp,%rax,4), %edi movl %edi, 404(%rsp) movl 404(%rsp), %eax addq $408, %rsp ## imm = 0x198 ret Now we generate: %arrayidx = getelementptr inbounds [100 x i32]* %A, i32 0, i64 %idxprom ; <i32> [#uses=1] %tmp1 = load i32 %arrayidx ; <i32> [#uses=1] ret i32 %tmp1 } and: _foo: ## @foo ## BB#0: ## %entry subq $408, %rsp ## imm = 0x198 movl %edi, 404(%rsp) movl 404(%rsp), %edi movslq %edi, %rax movl (%rsp,%rax,4), %eax addq $408, %rsp ## imm = 0x198 ret This actually does matter, cutting out 2000 lines of IR from CGStmt.ll for example. Another interesting effect is that altivec.h functions which are dead now get dce'd by the inliner. Hence all the changes to builtins-ppc-altivec.c to ensure the calls aren't dead. llvm-svn: 106970 2010-06-27 09:06:27 +08:00			`// CHECK: ret i32 1`
A not equal for an unordered relation should return true as specified in IEEE-754, e.g., NAN != NAN ? 1 : 0 should return 1. Also fix the case for complex. llvm-svn: 102598 2010-04-29 13:53:29 +08:00			`return (__builtin_nanf("") != __builtin_nanf("")) ? 1 : 0;`
			`}`