GlobalISel: correctly handle trivial fcmp predicates.

It makes sense to only do them once in IRTranslator rather than making everyone
deal with them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297304 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/GlobalISel/IRTranslator.cpp b/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 488869f..4d1ac68 100644 (file)
--- a/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -193,9 +193,12 @@ bool IRTranslator::translateCompare(const User &U,
   CmpInst::Predicate Pred =
       CI ? CI->getPredicate() : static_cast<CmpInst::Predicate>(
                                     cast<ConstantExpr>(U).getPredicate());
-
   if (CmpInst::isIntPredicate(Pred))
     MIRBuilder.buildICmp(Pred, Res, Op0, Op1);
+  else if (Pred == CmpInst::FCMP_FALSE)
+    MIRBuilder.buildConstant(Res, 0);
+  else if  (Pred == CmpInst::FCMP_TRUE)
+    MIRBuilder.buildConstant(Res, 1);
   else
     MIRBuilder.buildFCmp(Pred, Res, Op0, Op1);
 

diff --git a/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll b/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
index 1bbda24..c0cbf69 100644 (file)
--- a/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
+++ b/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
@@ -1056,6 +1056,17 @@ define void @float_comparison(float* %a.addr, float* %b.addr, i1* %bool.addr) {
   ret void
 }
 
+; CHECK-LABEL: name: trivial_float_comparison
+; CHECK: [[R1:%[0-9]+]](s1) = G_CONSTANT i1 false
+; CHECK: [[R2:%[0-9]+]](s1) = G_CONSTANT i1 true
+; CHECK: G_ADD [[R1]], [[R2]]
+define i1 @trivial_float_comparison(double %a, double %b) {
+  %r1 = fcmp false double %a, %b
+  %r2 = fcmp true double %a, %b
+  %sum = add i1 %r1, %r2
+  ret i1 %sum
+}
+
 @var = global i32 0
 
 define i32* @test_global() {