97a1570d8c
`X86InstrInfo::optimizeCompareInstr` would only optimize a `SUB` followed by a `CMP` in `isRedundantFlagInstr`. This extends the code to also look for other combinations like `CMP`+`CMP`, `TEST`+`TEST`, `SUB x,0`+`TEST`. - Change `isRedundantFlagInstr` to run `analyzeCompareInstr` on the candidate instruction and compare the results. This normalizes things and gives consistent results for various comparisons (`CMP x, y`, `SUB x, y`) and immediate cases (`TEST x, x`, `SUB x, 0`, `CMP x, 0`...). - Turn `isRedundantFlagInstr` into a member function so it can call `analyzeCompare`. - We now also check `isRedundantFlagInstr` even if `IsCmpZero` is true, since we now have cases like `TEST`+`TEST`. Differential Revision: https://reviews.llvm.org/D110865
52 lines
1.5 KiB
LLVM
52 lines
1.5 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc < %s -mtriple=i686-- | FileCheck %s
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define fastcc i32 @_Z18yy_get_next_bufferv() nounwind {
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; CHECK-LABEL: _Z18yy_get_next_bufferv:
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; CHECK: # %bb.0: # %entry
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; CHECK-NEXT: movl $42, %eax
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; CHECK-NEXT: cmpl $-1, %eax
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; CHECK-NEXT: je .LBB0_3
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; CHECK-NEXT: .p2align 4, 0x90
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; CHECK-NEXT: .LBB0_1: # %bb116
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; CHECK-NEXT: # =>This Inner Loop Header: Depth=1
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; CHECK-NEXT: movb %al, 0
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; CHECK-NEXT: cmpl $-1, %eax
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; CHECK-NEXT: jne .LBB0_1
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; CHECK-NEXT: .LBB0_3: # %bb158
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; CHECK-NEXT: movb %al, 0
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; CHECK-NEXT: xorl %eax, %eax
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; CHECK-NEXT: retl
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entry:
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br label %bb131
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bb116: ; preds = %bb131
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%tmp125126 = trunc i32 %c.1 to i8 ; <i8> [#uses=1]
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store i8 %tmp125126, i8* null, align 1
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br label %bb131
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bb131: ; preds = %bb116, %entry
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%c.2 = phi i32 [ %c.1, %bb116 ], [ 42, %entry ] ; <i32> [#uses=1]
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%c.1 = select i1 false, i32 0, i32 %c.2 ; <i32> [#uses=4]
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%tmp181 = icmp eq i32 %c.1, -1 ; <i1> [#uses=1]
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br i1 %tmp181, label %bb158, label %bb116
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bb158: ; preds = %bb131
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br i1 true, label %cond_true163, label %cond_next178
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cond_true163: ; preds = %bb158
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%tmp172173 = trunc i32 %c.1 to i8 ; <i8> [#uses=1]
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store i8 %tmp172173, i8* null, align 1
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br label %cond_next178
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cond_next178: ; preds = %cond_true163, %bb158
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%tmp180 = icmp eq i32 %c.1, -1 ; <i1> [#uses=1]
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br i1 %tmp180, label %cond_next184, label %cond_next199
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cond_next184: ; preds = %cond_next178
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ret i32 0
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cond_next199: ; preds = %cond_next178
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ret i32 0
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}
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