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2fedd64241
After r261154, we were only clearing flags if the known-zero register was
originally live-in to the basic block, but we have to do it even if not when
more than one COPY has been eliminated, otherwise the user of the first COPY
may still have <kill> marked.
E.g.
BB#N:
%X0 = COPY %XZR
STRXui %X0<kill>, <fi#0>
%X0 = COPY %XZR
STRXui %X0<kill>, <fi#1>
We can eliminate both copies, X0 is not live-in, but we must clear the kill on
the first store.
Unfortunately, I've been unable to come up with a non-fragile test for this.
I've only seen it in the wild with regalloc-created spills, and attempts to
reproduce that in a reasonable way run afoul of COPY coalescing. Even volatile
asm clobbers were moved around. Should fix the aarch64 bot though.
llvm-svn: 261175
95 lines
2.7 KiB
LLVM
95 lines
2.7 KiB
LLVM
; RUN: llc -mtriple=aarch64-linux-gnu -mcpu=cortex-a57 -verify-machineinstrs < %s | FileCheck %s
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; CHECK-LABEL: f_XX:
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; CHECK: cbz x[[REG:[0-9]+]], [[BB:.LBB.*]]
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; CHECK: [[BB]]:
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; CHECK-NOT: mov x[[REG]], xzr
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define i64 @f_XX(i64 %n, i64* nocapture readonly %P) {
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entry:
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%tobool = icmp eq i64 %n, 0
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br i1 %tobool, label %if.end, label %if.then
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if.then: ; preds = %entry
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%0 = load i64, i64* %P
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br label %if.end
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if.end: ; preds = %entry, %if.then
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%a.0 = phi i64 [ %0, %if.then ], [ 0, %entry ]
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ret i64 %a.0
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}
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; CHECK-LABEL: f_WW:
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; CHECK: cbz w[[REG:[0-9]+]], [[BB:.LBB.*]]
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; CHECK: [[BB]]:
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; CHECK-NOT: mov w[[REG]], wzr
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define i32 @f_WW(i32 %n, i32* nocapture readonly %P) {
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entry:
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%tobool = icmp eq i32 %n, 0
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br i1 %tobool, label %if.end, label %if.then
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if.then: ; preds = %entry
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%0 = load i32, i32* %P
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br label %if.end
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if.end: ; preds = %entry, %if.then
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%a.0 = phi i32 [ %0, %if.then ], [ 0, %entry ]
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ret i32 %a.0
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}
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; CHECK-LABEL: f_XW:
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; CHECK: cbz x[[REG:[0-9]+]], [[BB:.LBB.*]]
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; CHECK: [[BB]]:
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; CHECK-NOT: mov w[[REG]], wzr
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define i32 @f_XW(i64 %n, i32* nocapture readonly %P) {
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entry:
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%tobool = icmp eq i64 %n, 0
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br i1 %tobool, label %if.end, label %if.then
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if.then: ; preds = %entry
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%0 = load i32, i32* %P
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br label %if.end
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if.end: ; preds = %entry, %if.then
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%a.0 = phi i32 [ %0, %if.then ], [ 0, %entry ]
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ret i32 %a.0
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}
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; CHECK-LABEL: f_WX:
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; CHECK: cbz w[[REG:[0-9]+]], [[BB:.LBB.*]]
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; CHECK: [[BB]]:
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; CHECK: mov x[[REG]], xzr
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; Do not remove the mov in this case because we do not know if the upper bits
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; of the X register are zero.
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define i64 @f_WX(i32 %n, i64* nocapture readonly %P) {
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entry:
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%tobool = icmp eq i32 %n, 0
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br i1 %tobool, label %if.end, label %if.then
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if.then: ; preds = %entry
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%0 = load i64, i64* %P
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br label %if.end
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if.end: ; preds = %entry, %if.then
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%a.0 = phi i64 [ %0, %if.then ], [ 0, %entry ]
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ret i64 %a.0
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}
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; CHECK-LABEL: test_superreg:
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; CHECK: cbz x[[REG:[0-9]+]], [[BB:.LBB.*]]
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; CHECK: [[BB]]:
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; CHECK: str x[[REG]], [x1]
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; CHECK-NOT: mov w[[REG]], wzr
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; Because we returned w0 but x0 was marked live-in to the block, we didn't
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; remove the <kill> on the str leading to a verification failure.
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define i32 @test_superreg(i64 %in, i64* %dest) {
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%tst = icmp eq i64 %in, 0
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br i1 %tst, label %true, label %false
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false:
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ret i32 42
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true:
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store volatile i64 %in, i64* %dest
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ret i32 0
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}
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