From b31189f26297fe30214da3e8d14a4575d5fdd262 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Fri, 8 Jan 2010 19:02:23 +0000 Subject: [PATCH] fix PR5978 by peeling the loop so that we avoid shifting the result int by 8 for the first byte. While normally harmless, if the result is smaller than a byte, this shift is invalid. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93018 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ConstantFolding.cpp | 4 ++-- test/Transforms/ConstProp/loads.ll | 10 ++++++++++ 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp index 194cabaf978..4ae8859a257 100644 --- a/lib/Analysis/ConstantFolding.cpp +++ b/lib/Analysis/ConstantFolding.cpp @@ -398,8 +398,8 @@ static Constant *FoldReinterpretLoadFromConstPtr(Constant *C, BytesLoaded, TD)) return 0; - APInt ResultVal(IntType->getBitWidth(), 0); - for (unsigned i = 0; i != BytesLoaded; ++i) { + APInt ResultVal = APInt(IntType->getBitWidth(), RawBytes[BytesLoaded-1]); + for (unsigned i = 1; i != BytesLoaded; ++i) { ResultVal <<= 8; ResultVal |= APInt(IntType->getBitWidth(), RawBytes[BytesLoaded-1-i]); } diff --git a/test/Transforms/ConstProp/loads.ll b/test/Transforms/ConstProp/loads.ll index 9151d256b02..9fbba2b3552 100644 --- a/test/Transforms/ConstProp/loads.ll +++ b/test/Transforms/ConstProp/loads.ll @@ -110,3 +110,13 @@ define i16 @test12() { ; CHECK: @test12 ; CHECK: ret i16 98 } + + +; PR5978 +@g5 = constant i8 4 +define i1 @test13() { + %A = load i1* bitcast (i8* @g5 to i1*) + ret i1 %A +; CHECK: @test13 +; CHECK: ret i1 false +} -- 2.34.1