[llvm] 46ccefb - [CVP] Fix APInt ctor assertion with i1 urem

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2024-11-05T10:03:37+01:00
New Revision: 46ccefb1236bf29b2d752715373d407f2d4c3d61

URL: https://github.com/llvm/llvm-project/commit/46ccefb1236bf29b2d752715373d407f2d4c3d61
DIFF: https://github.com/llvm/llvm-project/commit/46ccefb1236bf29b2d752715373d407f2d4c3d61.diff

LOG: [CVP] Fix APInt ctor assertion with i1 urem

This is creating an APInt with value 2, which may not be well-defined
for i1 values. Fix this by replacing the Y.umul_sat(2) with
Y.uadd_sat(Y).

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
    llvm/test/Transforms/CorrelatedValuePropagation/urem.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
index f2856ae3bdf163..7f838340410b51 100644
--- a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
+++ b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -831,9 +831,7 @@ static bool expandUDivOrURem(BinaryOperator *Instr, const ConstantRange &XCR,
 
   // Even if we don't know X's range, the divisor may be so large, X can't ever
   // be 2x larger than that. I.e. if divisor is always negative.
-  if (!XCR.icmp(ICmpInst::ICMP_ULT,
-                YCR.umul_sat(APInt(YCR.getBitWidth(), 2))) &&
-      !YCR.isAllNegative())
+  if (!XCR.icmp(ICmpInst::ICMP_ULT, YCR.uadd_sat(YCR)) && !YCR.isAllNegative())
     return false;
 
   IRBuilder<> B(Instr);

diff  --git a/llvm/test/Transforms/CorrelatedValuePropagation/urem.ll b/llvm/test/Transforms/CorrelatedValuePropagation/urem.ll
index ec6461e29f1917..e69deaa73d73bb 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/urem.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/urem.ll
@@ -462,4 +462,13 @@ join:
   ret i8 %res
 }
 
+define i1 @urem_i1() {
+; CHECK-LABEL: @urem_i1(
+; CHECK-NEXT:    [[REM:%.*]] = urem i1 false, false
+; CHECK-NEXT:    ret i1 [[REM]]
+;
+  %rem = urem i1 false, false
+  ret i1 %rem
+}
+
 declare void @use(i1)