b061d86c69
This ports the logic we generate in instcombine for a single use x.with.overflow check for use in SCEV's analysis. The result is that we can prove trip counts for many checks, and (through existing logic) often discharge them. Motivation comes from compiling a simple example with -ftrapv. Differential Revision: https://reviews.llvm.org/D116499
86 lines
2.8 KiB
LLVM
86 lines
2.8 KiB
LLVM
; RUN: llc < %s -mcpu=a2 -verify-machineinstrs | FileCheck %s
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; RUN: llc < %s -mcpu=a2 -disable-lsr -verify-machineinstrs | FileCheck -check-prefix=NOLSR %s
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target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
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target triple = "powerpc64-unknown-linux-gnu"
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define void @main() #0 {
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entry:
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br i1 undef, label %for.end, label %for.body
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for.body: ; preds = %for.body, %entry
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 1, %entry ]
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%indvars.iv.next = add i64 %indvars.iv, 1
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32
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%exitcond = icmp eq i32 %lftr.wideiv, 0
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br i1 %exitcond, label %for.end, label %for.body
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; CHECK: @main
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; CHECK: li [[REG:[0-9]+]], -1
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; CHECK: rldic [[REG2:[0-9]+]], [[REG]], 0, 32
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; CHECK: mtctr [[REG2]]
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; CHECK: bdnz
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for.end: ; preds = %for.body, %entry
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ret void
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}
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define void @main1() #0 {
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entry:
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br i1 undef, label %for.end, label %for.body
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for.body: ; preds = %for.body, %entry
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 1, %entry ]
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%indvars.iv.next = add i64 %indvars.iv, 1
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%exitcond = icmp eq i64 %indvars.iv.next, 0
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br i1 %exitcond, label %for.end, label %for.body
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; CHECK: @main1
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; CHECK: li [[REG:[0-9]+]], -1
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; CHECK: mtctr [[REG]]
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; CHECK: bdnz
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for.end: ; preds = %for.body, %entry
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ret void
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}
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define void @main2() #0 {
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entry:
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br i1 undef, label %for.end, label %for.body
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for.body: ; preds = %for.body, %entry
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 1, %entry ]
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%indvars.iv.next = add i64 %indvars.iv, 1
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%exitcond = icmp eq i64 %indvars.iv.next, -100000
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br i1 %exitcond, label %for.end, label %for.body
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; CHECK: @main2
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; CHECK: lis [[REG:[0-9]+]], -2
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; CHECK: ori [[REG2:[0-9]+]], [[REG]], 31071
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; CHECK: mtctr [[REG2]]
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; CHECK: bdnz
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for.end: ; preds = %for.body, %entry
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ret void
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}
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define void @main3() #0 {
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entry:
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br i1 undef, label %for.end, label %for.body
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for.body: ; preds = %for.body, %entry
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 127984, %entry ]
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%indvars.iv.next = add i64 %indvars.iv, -16
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%exitcond = icmp eq i64 %indvars.iv.next, -16
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br i1 %exitcond, label %for.end, label %for.body
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; NOLSR: @main3
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; NOLSR: li [[REG:[0-9]+]], 8000
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; NOLSR: mtctr [[REG]]
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; NOLSR: bdnz
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for.end: ; preds = %for.body, %entry
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ret void
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}
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attributes #0 = { nounwind "less-precise-fpmad"="false" "frame-pointer"="non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
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