From a2e0f6b643e9cfbbd698dbc9eb0289e5e33f8dc9 Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Mon, 13 Feb 2012 23:05:18 +0000
Subject: [PATCH] Check against umin while converting fcmp into an icmp.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150425 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../InstCombine/InstCombineCompares.cpp       | 11 ++++++
 .../Transforms/InstCombine/2012-02-13-FCmp.ll | 35 +++++++++++++++++++
 2 files changed, 46 insertions(+)
 create mode 100644 test/Transforms/InstCombine/2012-02-13-FCmp.ll

diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 4a59d7055e9..bb7763ddeb6 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2714,6 +2714,17 @@ Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I,
         return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
       return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
     }
+  } else {
+    // See if the RHS value is < UnsignedMin.
+    APFloat SMin(RHS.getSemantics(), APFloat::fcZero, false);
+    SMin.convertFromAPInt(APInt::getMinValue(IntWidth), true,
+                          APFloat::rmNearestTiesToEven);
+    if (SMin.compare(RHS) == APFloat::cmpGreaterThan) { // umin > 12312.0
+      if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_UGT ||
+          Pred == ICmpInst::ICMP_UGE)
+        return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext()));
+      return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext()));
+    }
   }
 
   // Okay, now we know that the FP constant fits in the range [SMIN, SMAX] or
diff --git a/test/Transforms/InstCombine/2012-02-13-FCmp.ll b/test/Transforms/InstCombine/2012-02-13-FCmp.ll
new file mode 100644
index 00000000000..39b05946515
--- /dev/null
+++ b/test/Transforms/InstCombine/2012-02-13-FCmp.ll
@@ -0,0 +1,35 @@
+; RUN: opt -instcombine -S < %s | FileCheck %s
+; Radar 10803727
+@.str = private unnamed_addr constant [35 x i8] c"\0Ain_range input (should be 0): %f\0A\00", align 1
+@.str1 = external hidden unnamed_addr constant [35 x i8], align 1
+
+declare i32 @printf(i8*, ...)
+define i64 @_Z8tempCastj(i32 %val) uwtable ssp {
+entry:
+  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([35 x i8]* @.str1, i64 0, i64 0), i32 %val)
+  %conv = uitofp i32 %val to double
+  %call.i = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([35 x i8]* @.str, i64 0, i64 0), double %conv)
+  %cmp.i = fcmp oge double %conv, -1.000000e+00
+  br i1 %cmp.i, label %land.rhs.i, label %if.end.critedge
+; CHECK:  br i1 true, label %land.rhs.i, label %if.end.critedge
+
+land.rhs.i:                                       ; preds = %entry
+  %cmp1.i = fcmp olt double %conv, 1.000000e+00
+  br i1 %cmp1.i, label %if.then, label %if.end
+
+if.then:                                          ; preds = %land.rhs.i
+  %add = fadd double %conv, 5.000000e-01
+  %conv3 = fptosi double %add to i64
+  br label %return
+
+if.end.critedge:                                  ; preds = %entry
+  br label %if.end
+
+if.end:                                           ; preds = %if.end.critedge, %land.rhs.i
+  br label %return
+
+return:                                           ; preds = %if.end, %if.then
+  %retval.0 = phi i64 [ %conv3, %if.then ], [ -1, %if.end ]
+  ret i64 %retval.0
+}
+