Don't sign extend the char when expanding char -> int during

load(bitcast(char[4] to i32*)) evaluation.

llvm-svn: 65246

2 files changed, 14 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
index 9f72910cb75..cfd1bac7ba8 100644
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -11028,12 +11028,12 @@ static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI,
         APInt SingleChar(numBits, 0);
         if (TD->isLittleEndian()) {
           for (signed i = len-1; i >= 0; i--) {
-            SingleChar = (uint64_t) Str[i];
+            SingleChar = (uint64_t) Str[i] & UCHAR_MAX;
             StrVal = (StrVal << 8) | SingleChar;
           }
         } else {
           for (unsigned i = 0; i < len; i++) {
-            SingleChar = (uint64_t) Str[i];
+            SingleChar = (uint64_t) Str[i] & UCHAR_MAX;
             StrVal = (StrVal << 8) | SingleChar;
           }
           // Append NULL at the end.
diff --git a/llvm/test/Transforms/InstCombine/2009-02-21-LoadCST.ll b/llvm/test/Transforms/InstCombine/2009-02-21-LoadCST.ll
new file mode 100644
index 00000000000..2c126df1f14
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/2009-02-21-LoadCST.ll
@@ -0,0 +1,12 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {ret i32 3679669}
+; PR3595
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
+target triple = "i386-pc-linux-gnu"
+
+@.str1 = internal constant [4 x i8] c"\B5%8\00"
+
+define i32 @test() {
+  %rhsv = load i32* bitcast ([4 x i8]* @.str1 to i32*), align 1
+  ret i32 %rhsv
+}