llvm/test/CodeGen/X86/2007-10-12-CoalesceExtSubReg.ll
Dan Gohman 102f3851bb Eliminate the first have of the optimization which eliminates BRCOND
when the condition is constant. This optimization shouldn't be
necessary, because codegen shouldn't be able to find dead control
paths that the IR-level optimizer can't find. And it's undesirable,
because it encourages bugpoint to leave "br i1 false" branches
in its output. And it wasn't updating the CFG.

I updated all the tests I could, but some tests are too reduced
and I wasn't able to meaningfully preserve them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106748 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-24 15:04:11 +00:00

33 lines
1.2 KiB
LLVM

; RUN: llc < %s -march=x86 | not grep movb
define i16 @f(i32* %bp, i32* %ss) signext {
entry:
br label %cond_next127
cond_next127: ; preds = %cond_next391, %entry
%v.1 = phi i32 [ undef, %entry ], [ %tmp411, %cond_next391 ] ; <i32> [#uses=1]
%tmp149 = mul i32 0, %v.1 ; <i32> [#uses=0]
%tmp254 = and i32 0, 15 ; <i32> [#uses=1]
%tmp256 = and i32 0, 15 ; <i32> [#uses=2]
br label %cond_next391
cond_next391: ; preds = %cond_next127
%tmp393 = load i32* %ss, align 4 ; <i32> [#uses=1]
%tmp395 = load i32* %bp, align 4 ; <i32> [#uses=2]
%tmp396 = shl i32 %tmp393, %tmp395 ; <i32> [#uses=2]
%tmp398 = sub i32 32, %tmp256 ; <i32> [#uses=2]
%tmp399 = lshr i32 %tmp396, %tmp398 ; <i32> [#uses=1]
%tmp405 = lshr i32 %tmp396, 31 ; <i32> [#uses=1]
%tmp406 = add i32 %tmp405, -1 ; <i32> [#uses=1]
%tmp409 = lshr i32 %tmp406, %tmp398 ; <i32> [#uses=1]
%tmp411 = sub i32 %tmp399, %tmp409 ; <i32> [#uses=1]
%tmp422445 = add i32 %tmp254, 0 ; <i32> [#uses=1]
%tmp426447 = add i32 %tmp395, %tmp256 ; <i32> [#uses=1]
store i32 %tmp426447, i32* %bp, align 4
%tmp429448 = icmp ult i32 %tmp422445, 63 ; <i1> [#uses=1]
br i1 %tmp429448, label %cond_next127, label %UnifiedReturnBlock
UnifiedReturnBlock: ; preds = %cond_next391
ret i16 0
}