Handle overflow of 64-bit loop conditions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71008 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 4365adc629fcf671dccc48414efe51482750a8e4..23f75630b7658c8f6614693a502fff8a9f4f1e49 100644 (file)
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2027,9 +2027,10 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
 
       Scale = SSInt / CmpSSInt;
       int64_t NewCmpVal = CmpVal * Scale;
-      APInt Mul = APInt(BitWidth, NewCmpVal);
+      APInt Mul = APInt(BitWidth*2, CmpVal);
+      Mul = Mul * APInt(BitWidth*2, Scale);
       // Check for overflow.
-      if (Mul.getSExtValue() != NewCmpVal)
+      if (!Mul.isSignedIntN(BitWidth))
         continue;
 
       // Watch out for overflow.

diff --git a/test/Transforms/LoopStrengthReduce/2009-05-04-Overflow.ll b/test/Transforms/LoopStrengthReduce/2009-05-04-Overflow.ll
new file mode 100644 (file)
index 0000000..28a78ec
--- /dev/null
+++ b/test/Transforms/LoopStrengthReduce/2009-05-04-Overflow.ll
@@ -0,0 +1,122 @@
+; Check that we do not strength reduce to an overflowiong loop condition
+; RUN: llvm-as < %s | opt -loop-reduce | llvm-dis | not grep 4755160694556239428
+
+target datalayout = "e-p:64:64"
+target triple = "x86_64-unknown-linux-gnu"
+@"initialized$$$CFE_id_3d9e38d5_main" = linkonce global [3 x i64] [i64 6729544817907097974, i64 754394135718280480, i64 0]             
+@"initialized$main$$CFE_id_3d9e38d5_main" = linkonce global [512 x i64] zeroinitializer                
+
+define i32 @main() {
+"file loop.c, line 10, bb14":
+       %vals = alloca [512 x i64], align 16            
+       br label %"file loop.c, line 10, bb101"
+
+"file loop.c, line 10, bb101":         
+       br label %"file loop.c, line 10, in inner vector loop at depth 0, bb62"
+
+"file loop.c, line 10, in inner vector loop at depth 0, bb62":         
+       %"$SI_S13.0" = phi i64 [ 0, %"file loop.c, line 10, bb101" ], [ %r35, %"file loop.c, line 13, in inner vector loop at depth 0, bb63" ]          
+       %"$LC_S14.0" = phi i64 [ -256, %"file loop.c, line 10, bb101" ], [ %r37, %"file loop.c, line 13, in inner vector loop at depth 0, bb63" ]               
+       br label %"file loop.c, line 13, in inner vector loop at depth 0, bb63"
+
+"file loop.c, line 13, in inner vector loop at depth 0, bb63":         
+       %r3 = add i64 %"$SI_S13.0", ptrtoint ([512 x i64]* @"initialized$main$$CFE_id_3d9e38d5_main" to i64)            
+       %vals18 = bitcast [512 x i64]* %vals to i8*             
+       %ctg2 = getelementptr i8* %vals18, i64 %"$SI_S13.0"             
+       %r9 = inttoptr i64 %r3 to <2 x i64>*            
+       %r10 = load <2 x i64>* %r9, align 8             
+       %r12 = bitcast i8* %ctg2 to <2 x i64>*          
+       store <2 x i64> %r10, <2 x i64>* %r12, align 16
+       %tmp17 = inttoptr i64 %r3 to <2 x i64>*         
+       %r15 = getelementptr <2 x i64>* %tmp17, i64 1           
+       %r16 = load <2 x i64>* %r15, align 8            
+       %ctg2.sum19 = or i64 %"$SI_S13.0", 16           
+       %r19 = getelementptr i8* %vals18, i64 %ctg2.sum19               
+       %0 = bitcast i8* %r19 to <2 x i64>*             
+       store <2 x i64> %r16, <2 x i64>* %0, align 16
+       %tmp15 = inttoptr i64 %r3 to <2 x i64>*         
+       %r22 = getelementptr <2 x i64>* %tmp15, i64 2           
+       %r23 = load <2 x i64>* %r22, align 8            
+       %ctg2.sum20 = or i64 %"$SI_S13.0", 32           
+       %r26 = getelementptr i8* %vals18, i64 %ctg2.sum20               
+       %1 = bitcast i8* %r26 to <2 x i64>*             
+       store <2 x i64> %r23, <2 x i64>* %1, align 16
+       %tmp13 = inttoptr i64 %r3 to <2 x i64>*         
+       %r29 = getelementptr <2 x i64>* %tmp13, i64 3           
+       %r30 = load <2 x i64>* %r29, align 8            
+       %ctg2.sum21 = or i64 %"$SI_S13.0", 48           
+       %r33 = getelementptr i8* %vals18, i64 %ctg2.sum21               
+       %2 = bitcast i8* %r33 to <2 x i64>*             
+       store <2 x i64> %r30, <2 x i64>* %2, align 16
+       %r35 = add i64 %"$SI_S13.0", 64         
+       %r37 = add i64 %"$LC_S14.0", 4          
+       %r39 = icmp slt i64 %r37, 0             
+       br i1 %r39, label %"file loop.c, line 10, in inner vector loop at depth 0, bb62", label %"file loop.c, line 15, bb51"
+
+"file loop.c, line 15, bb51":          
+       %3 = getelementptr [512 x i64]* %vals, i64 0, i64 0             
+       store i64 0, i64* %3, align 16
+       br label %"file loop.c, line 10, in inner loop at depth 0, bb65"
+
+"file loop.c, line 10, in inner loop at depth 0, bb65":                
+       %"$vals_WR0_S15.0" = phi i64 [ 0, %"file loop.c, line 15, bb51" ], [ %r70, %"file loop.c, line 16, in inner loop at depth 0, bb67" ]            
+       %"$i_S16.0" = phi i64 [ 0, %"file loop.c, line 15, bb51" ], [ %r78, %"file loop.c, line 16, in inner loop at depth 0, bb67" ]           
+       br label %"file loop.c, line 16, in inner loop at depth 0, bb67"
+
+"file loop.c, line 16, in inner loop at depth 0, bb67":                
+       %r45 = add i64 %"$vals_WR0_S15.0", 81985529216486895            
+       %r5111 = or i64 %"$i_S16.0", 1          
+       %r5212 = getelementptr [512 x i64]* %vals, i64 0, i64 %r5111            
+       store i64 %r45, i64* %r5212, align 8
+       %r54 = add i64 %"$vals_WR0_S15.0", 163971058432973790           
+       %r599 = or i64 %"$i_S16.0", 2           
+       %r6010 = getelementptr [512 x i64]* %vals, i64 0, i64 %r599             
+       store i64 %r54, i64* %r6010, align 16
+       %r62 = add i64 %"$vals_WR0_S15.0", 245956587649460685           
+       %r677 = or i64 %"$i_S16.0", 3           
+       %r688 = getelementptr [512 x i64]* %vals, i64 0, i64 %r677              
+       store i64 %r62, i64* %r688, align 8
+       %r70 = add i64 %"$vals_WR0_S15.0", 327942116865947580           
+       %r75 = add i64 %"$i_S16.0", 4           
+       %r766 = getelementptr [512 x i64]* %vals, i64 0, i64 %r75               
+       store i64 %r70, i64* %r766, align 16
+       %r78 = add i64 %"$i_S16.0", 4           
+       %r80 = icmp slt i64 %r78, 508           
+       br i1 %r80, label %"file loop.c, line 10, in inner loop at depth 0, bb65", label %"file loop.c, line 16, bb39"
+
+"file loop.c, line 16, bb39":          
+       %r84 = add i64 %"$vals_WR0_S15.0", 409927646082434475           
+       %r885 = getelementptr [512 x i64]* %vals, i64 0, i64 509                
+       store i64 %r84, i64* %r885, align 8
+       %r90 = add i64 %"$vals_WR0_S15.0", 491913175298921370           
+       %r944 = getelementptr [512 x i64]* %vals, i64 0, i64 510                
+       store i64 %r90, i64* %r944, align 16
+       %r1003 = getelementptr [512 x i64]* %vals, i64 0, i64 511               
+       %r96.c = add i64 %"$vals_WR0_S15.0", 573898704515408265         
+       store i64 %r96.c, i64* %r1003, align 8
+       br label %"file loop.c, line 10, in inner loop at depth 0, bb13"
+
+"file loop.c, line 10, in inner loop at depth 0, bb13":                
+       %"$i_S17.0" = phi i64 [ 0, %"file loop.c, line 16, bb39" ], [ %r111, %"file loop.c, line 19, in inner loop at depth 0, bb25" ]          
+       br label %"file loop.c, line 19, in inner loop at depth 0, bb6"
+
+"file loop.c, line 19, in inner loop at depth 0, bb6":         
+       %r102 = add i64 %"$i_S17.0", 1          
+       %r106 = add i64 %"$i_S17.0", 1          
+       %r1071 = getelementptr [512 x i64]* %vals, i64 0, i64 %r106             
+       %r1072 = load i64* %r1071, align 8              
+       %r109 = call i32 (...)* @printf([17 x i8]* bitcast ([3 x i64]* @"initialized$$$CFE_id_3d9e38d5_main" to [17 x i8]*), i64 %r102, i64 %r1072)             
+       br label %"file loop.c, line 19, in inner loop at depth 0, bb25"
+
+"file loop.c, line 19, in inner loop at depth 0, bb25":                
+       %r111 = add i64 %"$i_S17.0", 1          
+       %r113 = icmp slt i64 %r111, 511         
+       br i1 %r113, label %"file loop.c, line 10, in inner loop at depth 0, bb13", label %"file loop.c, line 19, bb10"
+
+"file loop.c, line 19, bb10":
+       ret i32 0
+}
+
+declare i8* @llvm.returnaddress(i32) nounwind readnone
+
+declare i32 @printf(...)