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55357e1fa3
In PR20308 ( http://llvm.org/bugs/show_bug.cgi?id=20308 ), the critical-anti-dependency breaker caused a miscompile because it broke a WAR hazard using a register that it thinks is available based on info from a kill inst. Until PR18663 is solved, we shouldn't use any def/use info from a kill because they are really just nops. This patch adds guard checks for kills around calls to ScanInstruction() where the DefIndices array is set. For good measure, add an assert in ScanInstruction() so we don't hit this bug again. The test case is a reduced version of the code from the bug report. Differential Revision: http://reviews.llvm.org/D4977 llvm-svn: 216114
29 lines
1.3 KiB
LLVM
29 lines
1.3 KiB
LLVM
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -relocation-model=pic -post-RA-scheduler=1 -break-anti-dependencies=critical | FileCheck %s
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; PR20308 ( http://llvm.org/bugs/show_bug.cgi?id=20308 )
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; The critical-anti-dependency-breaker must not use register def information from a kill inst.
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; This test case expects such an instruction to appear as a comment with def info for RDI.
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; There is an anti-dependency (WAR) hazard using RAX using default reg allocation and scheduling.
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; The post-RA-scheduler and critical-anti-dependency breaker can eliminate that hazard using R10.
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; That is the first free register that isn't used as a param in the call to "@Image".
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@PartClass = external global i32
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@NullToken = external global i64
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; CHECK-LABEL: Part_Create:
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; CHECK-DAG: # kill: RDI<def>
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; CHECK-DAG: movq PartClass@GOTPCREL(%rip), %r10
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define i32 @Part_Create(i64* %Anchor, i32 %TypeNum, i32 %F, i32 %Z, i32* %Status, i64* %PartTkn) {
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%PartObj = alloca i64*, align 8
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%Vchunk = alloca i64, align 8
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%1 = load i64* @NullToken, align 4
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store i64 %1, i64* %Vchunk, align 8
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%2 = load i32* @PartClass, align 4
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call i32 @Image(i64* %Anchor, i32 %2, i32 0, i32 0, i32* %Status, i64* %PartTkn, i64** %PartObj)
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call i32 @Create(i64* %Anchor)
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ret i32 %2
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}
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declare i32 @Image(i64*, i32, i32, i32, i32*, i64*, i64**)
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declare i32 @Create(i64*)
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