Fix translateX86CC: if SetCCOpcode is SETULE and

LHS is a foldable load, then LHS and RHS are swapped
and SetCCOpcode is changed to SETUGT.  But the later
code is expecting operands to be the wrong way round
for SETUGT, but they are not in this case, resulting
in an inverted compare.  The solution is to move the
load normalization before the correction for SETUGT.
This bug was tickled by LegalizeTypes which happened
to legalize the testcase slightly differently to
LegalizeDAG.

llvm-svn: 58092

2 files changed, 27 insertions, 13 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index c0831a734a9..3dbedba7b96 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -1970,28 +1970,25 @@ static bool translateX86CC(ISD::CondCode SetCCOpcode, bool isFP,
     case ISD::SETUGE: X86CC = X86::COND_AE; break;
     }
   } else {
-    // First determine if it requires or is profitable to flip the operands.
-    bool Flip = false;
+    // First determine if it is required or is profitable to flip the operands.
+
+    // If LHS is a foldable load, but RHS is not, flip the condition.
+    if ((ISD::isNON_EXTLoad(LHS.getNode()) && LHS.hasOneUse()) &&
+        !(ISD::isNON_EXTLoad(RHS.getNode()) && RHS.hasOneUse())) {
+      SetCCOpcode = getSetCCSwappedOperands(SetCCOpcode);
+      std::swap(LHS, RHS);
+    }
+
     switch (SetCCOpcode) {
     default: break;
     case ISD::SETOLT:
     case ISD::SETOLE:
     case ISD::SETUGT:
     case ISD::SETUGE:
-      Flip = true;
+      std::swap(LHS, RHS);
       break;
     }
 
-    // If LHS is a foldable load, but RHS is not, flip the condition.
-    if (!Flip &&
-        (ISD::isNON_EXTLoad(LHS.getNode()) && LHS.hasOneUse()) &&
-        !(ISD::isNON_EXTLoad(RHS.getNode()) && RHS.hasOneUse())) {
-      SetCCOpcode = getSetCCSwappedOperands(SetCCOpcode);
-      Flip = true;
-    }
-    if (Flip)
-      std::swap(LHS, RHS);
-
     // On a floating point condition, the flags are set as follows:
     // ZF  PF  CF   op
     //  0 | 0 | 0 | X > Y
diff --git a/llvm/test/CodeGen/X86/2008-10-24-FlippedCompare.ll b/llvm/test/CodeGen/X86/2008-10-24-FlippedCompare.ll
new file mode 100644
index 00000000000..8a7987db599
--- /dev/null
+++ b/llvm/test/CodeGen/X86/2008-10-24-FlippedCompare.ll
@@ -0,0 +1,17 @@
+; RUN: llvm-as < %s | llc -enable-legalize-types -march=x86 -mattr=+sse2 -o - | not grep {ucomiss\[^,\]*esp}
+
+define void @f(float %wt) {
+entry:
+	%0 = fcmp ogt float %wt, 0.000000e+00		; <i1> [#uses=1]
+	%1 = tail call i32 @g(i32 44)		; <i32> [#uses=3]
+	%2 = inttoptr i32 %1 to i8*		; <i8*> [#uses=2]
+	br i1 %0, label %bb, label %bb1
+
+bb:		; preds = %entry
+	ret void
+
+bb1:		; preds = %entry
+	ret void
+}
+
+declare i32 @g(i32)