llvm-6502/test/CodeGen/X86/i8-umulo.ll
Andrea Di Biagio 0bedfa456a [X86] Fix checked arithmetic for i8 on X86.
When lowering a ISD::BRCOND into a test+branch, make sure that we
always use the correct condition code to emit the test operation.

This fixes PR19858: "i8 checked mul is wrong on x86".

Patch by Keno Fisher!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210032 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-02 16:00:27 +00:00

25 lines
619 B
LLVM

; RUN: llc -mcpu=generic -march=x86 < %s | FileCheck %s
; PR19858
declare {i8, i1} @llvm.umul.with.overflow.i8(i8 %a, i8 %b)
define i8 @testumulo(i32 %argc) {
; CHECK: imulw
; CHECK: testb %{{.+}}, %{{.+}}
; CHECK: je [[NOOVERFLOWLABEL:.+]]
; CHECK: {{.*}}[[NOOVERFLOWLABEL]]:
; CHECK-NEXT: movb
; CHECK-NEXT: retl
top:
%RHS = trunc i32 %argc to i8
%umul = call { i8, i1 } @llvm.umul.with.overflow.i8(i8 25, i8 %RHS)
%ex = extractvalue { i8, i1 } %umul, 1
br i1 %ex, label %overflow, label %nooverlow
overflow:
ret i8 %RHS
nooverlow:
%umul.value = extractvalue { i8, i1 } %umul, 0
ret i8 %umul.value
}