[llvm] r233541 - [SystemZ] Fix LLVM crash on unoptimized code

[Ulrich Weigand]

Author: uweigand
Date: Mon Mar 30 08:46:59 2015
New Revision: 233541

URL: http://llvm.org/viewvc/llvm-project?rev=233541&view=rev
Log:
[SystemZ] Fix LLVM crash on unoptimized code

Compiling the following function with -O0 would crash, since LLVM would
hit an assertion in getTestUnderMaskCond:

  int test(unsigned long x)
  {
    return x >= 0 && x <= 15;
  }

Fixed by detecting the case in the caller of getTestUnderMaskCond.


Added:
    llvm/trunk/test/CodeGen/SystemZ/int-cmp-50.ll
Modified:
    llvm/trunk/lib/Target/SystemZ/SystemZISelLowering.cpp

Modified: llvm/trunk/lib/Target/SystemZ/SystemZISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/SystemZ/SystemZISelLowering.cpp?rev=233541&r1=233540&r2=233541&view=diff
==============================================================================
--- llvm/trunk/lib/Target/SystemZ/SystemZISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/SystemZ/SystemZISelLowering.cpp Mon Mar 30 08:46:59 2015
@@ -1530,6 +1530,8 @@ static void adjustForTestUnderMask(Selec
     MaskVal = -(CmpVal & -CmpVal);
     NewC.ICmpType = SystemZICMP::UnsignedOnly;
   }
+  if (!MaskVal)
+    return;
 
   // Check whether the combination of mask, comparison value and comparison
   // type are suitable.

Added: llvm/trunk/test/CodeGen/SystemZ/int-cmp-50.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/SystemZ/int-cmp-50.ll?rev=233541&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/SystemZ/int-cmp-50.ll (added)
+++ llvm/trunk/test/CodeGen/SystemZ/int-cmp-50.ll Mon Mar 30 08:46:59 2015
@@ -0,0 +1,30 @@
+; Verify that we do not crash on always-true conditions
+;
+; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z10 -O0
+;
+; This test was compiled using clang -O0 from the following source code:
+;
+; int test(unsigned long x)
+; {
+;   return x >= 0 && x <= 15;
+; }
+
+define signext i32 @test(i64 %x) {
+entry:
+  %x.addr = alloca i64, align 8
+  store i64 %x, i64* %x.addr, align 8
+  %0 = load i64, i64* %x.addr, align 8
+  %cmp = icmp uge i64 %0, 0
+  br i1 %cmp, label %land.rhs, label %land.end
+
+land.rhs:                                         ; preds = %entry
+  %1 = load i64, i64* %x.addr, align 8
+  %cmp1 = icmp ule i64 %1, 15
+  br label %land.end
+
+land.end:                                         ; preds = %land.rhs, %entry
+  %2 = phi i1 [ false, %entry ], [ %cmp1, %land.rhs ]
+  %land.ext = zext i1 %2 to i32
+  ret i32 %land.ext
+}
+