From 4047f4a0b478e20e981cc46d2aa0ca3141f79f07 Mon Sep 17 00:00:00 2001
From: Duncan Sands <baldrick@free.fr>
Date: Fri, 24 Oct 2008 13:03:10 +0000
Subject: [PATCH] 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58092 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp            | 23 ++++++++-----------
 test/CodeGen/X86/2008-10-24-FlippedCompare.ll | 17 ++++++++++++++
 2 files changed, 27 insertions(+), 13 deletions(-)
 create mode 100644 test/CodeGen/X86/2008-10-24-FlippedCompare.ll

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index c0831a734a9..3dbedba7b96 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/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/test/CodeGen/X86/2008-10-24-FlippedCompare.ll b/test/CodeGen/X86/2008-10-24-FlippedCompare.ll
new file mode 100644
index 00000000000..8a7987db599
--- /dev/null
+++ b/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)