[llvm-commits] [llvm] r157548 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineShifts.cpp test/Transforms/InstCombine/2012-05-27-Negative-Shift-Crash.ll

[Benjamin Kramer]

Author: d0k
Date: Sun May 27 17:03:32 2012
New Revision: 157548

URL: http://llvm.org/viewvc/llvm-project?rev=157548&view=rev
Log:
PR12967: Don't crash when trying to fold a shift that's larger than the type's size.

Added:
    llvm/trunk/test/Transforms/InstCombine/2012-05-27-Negative-Shift-Crash.ll
Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp?rev=157548&r1=157547&r2=157548&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp Sun May 27 17:03:32 2012
@@ -151,7 +151,7 @@
 
     // We can always turn lshr(c1)+shl(c2) -> lshr(c3)+and(c4), but it isn't
     // profitable unless we know the and'd out bits are already zero.
-    if (CI->getZExtValue() > NumBits) {
+    if (CI->getValue().ult(TypeWidth) && CI->getZExtValue() > NumBits) {
       unsigned LowBits = CI->getZExtValue() - NumBits;
       if (MaskedValueIsZero(I->getOperand(0),
                           APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits))

Added: llvm/trunk/test/Transforms/InstCombine/2012-05-27-Negative-Shift-Crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2012-05-27-Negative-Shift-Crash.ll?rev=157548&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2012-05-27-Negative-Shift-Crash.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/2012-05-27-Negative-Shift-Crash.ll Sun May 27 17:03:32 2012
@@ -0,0 +1,61 @@
+; RUN: opt -inline -instcombine -S < %s
+; PR12967
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.7.0"
+
+ at d = common global i32 0, align 4
+ at c = common global i32 0, align 4
+ at e = common global i32 0, align 4
+ at f = common global i32 0, align 4
+ at a = common global i32 0, align 4
+ at b = common global i32 0, align 4
+
+define signext i8 @fn1(i32 %p1) nounwind uwtable readnone ssp {
+entry:
+  %shr = lshr i32 1, %p1
+  %conv = trunc i32 %shr to i8
+  ret i8 %conv
+}
+
+define void @fn4() nounwind uwtable ssp {
+entry:
+  %0 = load i32* @d, align 4, !tbaa !0
+  %cmp = icmp eq i32 %0, 0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @c, align 4, !tbaa !0
+  tail call void @fn3(i32 %conv) nounwind
+  ret void
+}
+
+define void @fn3(i32 %p1) nounwind uwtable ssp {
+entry:
+  %and = and i32 %p1, 8
+  store i32 %and, i32* @e, align 4, !tbaa !0
+  %sub = add nsw i32 %and, -1
+  store i32 %sub, i32* @f, align 4, !tbaa !0
+  %0 = load i32* @a, align 4, !tbaa !0
+  %tobool = icmp eq i32 %0, 0
+  br i1 %tobool, label %if.else, label %if.then
+
+if.then:                                          ; preds = %entry
+  %1 = load i32* @b, align 4, !tbaa !0
+  %.lobit = lshr i32 %1, 31
+  %2 = trunc i32 %.lobit to i8
+  %.not = xor i8 %2, 1
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  %call = tail call signext i8 @fn1(i32 %sub) nounwind
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %storemerge.in = phi i8 [ %call, %if.else ], [ %.not, %if.then ]
+  %storemerge = sext i8 %storemerge.in to i32
+  store i32 %storemerge, i32* @b, align 4
+  ret void
+}
+
+!0 = metadata !{metadata !"int", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA"}