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[PowerPC] [FastISel] i1 constants must be zero extended 

When materializing constant i1 values, they must be zero extended. We represent
i1 values as [0, 1], not [0, -1], in i32 registers. As it turns out, this code
path was dead for i1 values prior to r216006 (which is why this did not manifest in
miscompiles until recently).

Fixes -O0 self-hosting on PPC64/Linux.

llvm-svn: 224842
This commit is contained in:
Hal Finkel 2014-12-25 23:08:25 +00:00
parent b723834d82
commit 0c505b08a5
2 changed files with 28 additions and 1 deletions
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2
llvm/lib/Target/PowerPC/PPCFastISel.cpp
View File

@ -2109,7 +2109,7 @@ unsigned PPCFastISel::fastMaterializeConstant(const Constant *C) {
else if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
return PPCMaterializeGV(GV, VT);
else if (isa<ConstantInt>(C))
return PPCMaterializeInt(C, VT);
return PPCMaterializeInt(C, VT, VT != MVT::i1);
return 0;
}

27
llvm/test/CodeGen/PowerPC/fast-isel-const.ll Normal file
View File

@ -0,0 +1,27 @@
; RUN: llc < %s -O0 -verify-machineinstrs -fast-isel-abort -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr7 -mattr=-vsx | FileCheck %s --check-prefix=ELF64
define zeroext i1 @testi1(i8 %in) nounwind uwtable ssp {
entry:
%c = icmp eq i8 %in, 5
br i1 %c, label %true, label %false
; ELF64-LABEL: @testi1
true:
br label %end
; ELF64-NOT: li {{[0-9]+}}, -1
; ELF64: li {{[0-9]+}}, 1
false:
br label %end
; ELF64: li {{[0-9]+}}, 0
end:
%r = phi i1 [ 0, %false], [ 1, %true ]
ret i1 %r
; ELF64: blr
}