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(i64 (zext (srl GR32 8))) -> movzbl AH is not safe since srl 8 only clear the top 8 bits. 

llvm-svn: 72618
This commit is contained in:
Evan Cheng 2009-05-30 08:43:27 +00:00
parent 5f478b78c0
commit 7142ad75a1
2 changed files with 28 additions and 7 deletions
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7
llvm/lib/Target/X86/X86Instr64bit.td
View File

@ -1607,13 +1607,6 @@ def : Pat<(and (srl_su GR32:$src, (i8 8)), (i32 255)),
(EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_ABCD),
x86_subreg_8bit_hi))>,
Requires<[In64BitMode]>;
def : Pat<(i64 (zext (srl_su GR32:$src, (i8 8)))),
(SUBREG_TO_REG
(i64 0),
(MOVZX32_NOREXrr8
(EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_ABCD),
x86_subreg_8bit_hi)),
x86_subreg_32bit)>;
def : Pat<(srl_su GR16:$src, (i8 8)),
(EXTRACT_SUBREG
(MOVZX32_NOREXrr8

28
llvm/test/CodeGen/X86/2009-05-30-ISelBug.ll Normal file
View File

@ -0,0 +1,28 @@
; RUN: llvm-as < %s | llc -march=x86-64 | not grep {movzbl %\[abcd\]h,}
define void @BZ2_bzDecompress_bb5_2E_outer_bb35_2E_i_bb54_2E_i(i32*, i32 %c_nblock_used.2.i, i32 %.reload51, i32* %.out, i32* %.out1, i32* %.out2, i32* %.out3) nounwind {
newFuncRoot:
br label %bb54.i
bb35.i.backedge.exitStub: ; preds = %bb54.i
store i32 %6, i32* %.out
store i32 %10, i32* %.out1
store i32 %11, i32* %.out2
store i32 %12, i32* %.out3
ret void
bb54.i: ; preds = %newFuncRoot
%1 = zext i32 %.reload51 to i64 ; <i64> [#uses=1]
%2 = getelementptr i32* %0, i64 %1 ; <i32*> [#uses=1]
%3 = load i32* %2, align 4 ; <i32> [#uses=2]
%4 = lshr i32 %3, 8 ; <i32> [#uses=1]
%5 = and i32 %3, 255 ; <i32> [#uses=1]
%6 = add i32 %5, 4 ; <i32> [#uses=1]
%7 = zext i32 %4 to i64 ; <i64> [#uses=1]
%8 = getelementptr i32* %0, i64 %7 ; <i32*> [#uses=1]
%9 = load i32* %8, align 4 ; <i32> [#uses=2]
%10 = and i32 %9, 255 ; <i32> [#uses=1]
%11 = lshr i32 %9, 8 ; <i32> [#uses=1]
%12 = add i32 %c_nblock_used.2.i, 5 ; <i32> [#uses=1]
br label %bb35.i.backedge.exitStub
}