Index: lib/Transforms/Scalar/LoopStrengthReduce.cpp
===================================================================
--- lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2027,6 +2027,12 @@
     if (!PH) continue;
     if (PH->getNumIncomingValues() != 2) continue;
 
+    // If the calculation in integers overflows, the result in FP type will
+    // differ. So we only can do this transformation if we are guaranteed to not
+    // deal with overflowing values.
+    const SCEVAddRecExpr *PS = dyn_cast<SCEVAddRecExpr>(SE.getSCEV(PH));
+    if (!PS || !PS->hasNoSelfWrap()) continue;
+
     Type *SrcTy = PH->getType();
     int Mantissa = DestTy->getFPMantissaWidth();
     if (Mantissa == -1) continue;
Index: test/Transforms/LoopStrengthReduce/X86/2008-08-14-ShadowIV.ll
===================================================================
--- test/Transforms/LoopStrengthReduce/X86/2008-08-14-ShadowIV.ll
+++ test/Transforms/LoopStrengthReduce/X86/2008-08-14-ShadowIV.ll
@@ -18,7 +18,7 @@
 	tail call void @bar( i32 %i.03 ) nounwind
 	uitofp i32 %i.03 to double		; <double>:1 [#uses=1]
 	tail call void @foo( double %1 ) nounwind
-	%indvar.next = add i32 %i.03, 1		; <i32> [#uses=2]
+	%indvar.next = add nuw i32 %i.03, 1		; <i32> [#uses=2]
 	%exitcond = icmp eq i32 %indvar.next, %umax		; <i1> [#uses=1]
 	br i1 %exitcond, label %return, label %bb
 
@@ -43,7 +43,7 @@
 	tail call void @bar( i32 %1 ) nounwind
 	uitofp i64 %i.03 to double		; <double>:2 [#uses=1]
 	tail call void @foo( double %2 ) nounwind
-	%indvar.next = add i64 %i.03, 1		; <i64> [#uses=2]
+	%indvar.next = add nuw i64 %i.03, 1		; <i64> [#uses=2]
 	%exitcond = icmp eq i64 %indvar.next, %umax		; <i1> [#uses=1]
 	br i1 %exitcond, label %return, label %bb
 
Index: test/Transforms/LoopStrengthReduce/dont_turn_int_overflow_to_fp.ll
===================================================================
--- /dev/null
+++ test/Transforms/LoopStrengthReduce/dont_turn_int_overflow_to_fp.ll
@@ -0,0 +1,59 @@
+; RUN: opt < %s -loop-reduce -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:1"
+target triple = "x86_64-unknown-linux-gnu"
+
+; This test checks that we don't try to replace integer calculations with
+; double calculations if we cannot prove that integer calculations will not
+; overflow.
+
+define i32 @test_01() {
+; CHECK-LABEL:  test_01(
+; CHECK:          outer_header:
+; CHECK-NOT:      phi double
+; CHECK-NOT:      phi float
+entry:
+  br label %outer_header
+
+outer_header:                                           ; preds = %outer_backedge, %entry
+  %local_3_ = phi i32 [ -4, %entry ], [ %tmp10, %outer_backedge ]
+  %local_4_ = phi i32 [ -3220, %entry ], [ %tmp5, %outer_backedge ]
+  %local_6_ = phi i32 [ 12, %entry ], [ %tmp6, %outer_backedge ]
+  %tmp1 = sitofp i32 %local_4_ to double
+  %tmp2 = fsub double 0.000000e+00, %tmp1
+  %arg.v.i.peel = insertelement <2 x double> undef, double %tmp2, i32 0
+  %res.i.peel = call i32 @llvm.x86.sse2.cvttsd2si(<2 x double> %arg.v.i.peel)
+  %tmp3 = add i32 %local_4_, 1
+  %tmp4 = add i32 %res.i.peel, %local_3_
+  br label %inner_loop
+
+inner_loop:                                           ; preds = %inner_loop, %outer_header
+  %local_3_11 = phi i32 [ %tmp4, %outer_header ], [ %tmp10, %inner_loop ]
+  %local_4_12 = phi i32 [ %tmp3, %outer_header ], [ %tmp12, %inner_loop ]
+  %local_7_ = phi i32 [ 2, %outer_header ], [ %tmp13, %inner_loop ]
+  %tmp8 = sitofp i32 %local_4_12 to double
+  %tmp9 = fsub double 0.000000e+00, %tmp8
+  %arg.v.i = insertelement <2 x double> undef, double %tmp9, i32 0
+  %res.i = call i32 @llvm.x86.sse2.cvttsd2si(<2 x double> %arg.v.i) #1
+  %tmp10 = add i32 %res.i, %local_3_11
+  %tmp11 = mul i32 %local_7_, %local_7_
+  %tmp12 = add i32 %tmp11, %local_4_12
+  %tmp13 = add nuw nsw i32 %local_7_, 1
+  %tmp14 = icmp ugt i32 %local_7_, 305
+  br i1 %tmp14, label %outer_backedge, label %inner_loop
+
+outer_backedge:                                           ; preds = %inner_loop
+  %tmp5 = add i32 %local_4_, 9597741
+  %tmp6 = add nuw nsw i32 %local_6_, 1
+  %tmp7 = icmp ugt i32 %local_6_, 235
+  br i1 %tmp7, label %exit, label %outer_header
+
+exit:                                           ; preds = %outer_backedge
+  ret i32 %tmp10
+}
+
+; Function Attrs: nounwind readnone
+declare i32 @llvm.x86.sse2.cvttsd2si(<2 x double>) #0
+
+attributes #0 = { nounwind readnone }
+attributes #1 = { nounwind }