a105877646
The idea behind this canonicalization is that it allows us to handle less patterns, because we know that some will be canonicalized away. This is indeed very useful to e.g. know that constants are always on the right. However, this is only useful if the canonicalization is actually reliable. This is the case for constants, but not for arguments: Moving these to the right makes it look like the "more complex" expression is guaranteed to be on the left, but this is not actually the case in practice. It fails as soon as you replace the argument with another instruction. The end result is that it looks like things correctly work in tests, while they actually don't. We use the "thwart complexity-based canonicalization" trick to handle this in tests, but it's often a challenge for new contributors to get this right, and based on the regressions this PR originally exposed, we clearly don't get this right in many cases. For this reason, I think that it's better to remove this complexity canonicalization. It will make it much easier to write tests for commuted cases and make sure that they are handled.
314 lines
11 KiB
LLVM
314 lines
11 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; REQUIRES: x86-registered-target
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; RUN: opt < %s -passes=reassociate,instcombine -S | FileCheck %s --check-prefixes=CHECK,REASSOC_AND_IC --allow-unused-prefixes
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; RUN: opt < %s -O2 -S | FileCheck %s --check-prefixes=CHECK,O2 --allow-unused-prefixes
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target triple = "x86_64--"
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; Test cases in this file are intended to be run with both reassociate and
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; instcombine passes enabled.
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;
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; Test numbering remains continuous across:
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; - InstCombine/fast-basictest.ll
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; - PhaseOrdering/fast-basictest.ll
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; - PhaseOrdering/fast-reassociate-gvn.ll
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; - Reassociate/fast-basictest.ll
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; test2 ... test18 - both reassociate and instcombine passes
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; are required to perform a transform
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; ((a + (-3)) + b) + 3 -> a + b
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define float @test2(float %reg109, float %reg1111) {
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; CHECK-LABEL: @test2(
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; CHECK-NEXT: [[REG117:%.*]] = fadd fast float [[REG109:%.*]], [[REG1111:%.*]]
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; CHECK-NEXT: ret float [[REG117]]
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;
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%reg115 = fadd fast float %reg109, -3.000000e+01
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%reg116 = fadd fast float %reg115, %reg1111
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%reg117 = fadd fast float %reg116, 3.000000e+01
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ret float %reg117
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}
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; Verify that fold is not done without 'fast'
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define float @test2_no_FMF(float %reg109, float %reg1111) {
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; CHECK-LABEL: @test2_no_FMF(
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; CHECK-NEXT: [[REG115:%.*]] = fadd float [[REG109:%.*]], -3.000000e+01
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; CHECK-NEXT: [[REG116:%.*]] = fadd float [[REG115]], [[REG1111:%.*]]
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; CHECK-NEXT: [[REG117:%.*]] = fadd float [[REG116]], 3.000000e+01
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; CHECK-NEXT: ret float [[REG117]]
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;
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%reg115 = fadd float %reg109, -3.000000e+01
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%reg116 = fadd float %reg115, %reg1111
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%reg117 = fadd float %reg116, 3.000000e+01
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ret float %reg117
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}
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define float @test2_reassoc(float %reg109, float %reg1111) {
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; CHECK-LABEL: @test2_reassoc(
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; CHECK-NEXT: [[REG115:%.*]] = fadd reassoc float [[REG109:%.*]], -3.000000e+01
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; CHECK-NEXT: [[REG116:%.*]] = fadd reassoc float [[REG115]], [[REG1111:%.*]]
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; CHECK-NEXT: [[REG117:%.*]] = fadd reassoc float [[REG116]], 3.000000e+01
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; CHECK-NEXT: ret float [[REG117]]
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;
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%reg115 = fadd reassoc float %reg109, -3.000000e+01
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%reg116 = fadd reassoc float %reg115, %reg1111
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%reg117 = fadd reassoc float %reg116, 3.000000e+01
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ret float %reg117
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}
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; (x1 * 47) + (x2 * -47) => (x1 - x2) * 47
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define float @test13(float %X1, float %X2) {
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; CHECK-LABEL: @test13(
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; CHECK-NEXT: [[TMP1:%.*]] = fsub fast float [[X1:%.*]], [[X2:%.*]]
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; CHECK-NEXT: [[TMP2:%.*]] = fmul fast float [[TMP1]], 4.700000e+01
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; CHECK-NEXT: ret float [[TMP2]]
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;
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%B = fmul fast float %X1, 47. ; X1*47
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%C = fmul fast float %X2, -47. ; X2*-47
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%D = fadd fast float %B, %C ; X1*47 + X2*-47 -> 47*(X1-X2)
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ret float %D
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}
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; Check again with 'reassoc' and 'nsz' ('nsz' not technically required).
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define float @test13_reassoc_nsz(float %X1, float %X2) {
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; CHECK-LABEL: @test13_reassoc_nsz(
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; CHECK-NEXT: [[TMP1:%.*]] = fsub reassoc nsz float [[X1:%.*]], [[X2:%.*]]
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; CHECK-NEXT: [[TMP2:%.*]] = fmul reassoc nsz float [[TMP1]], 4.700000e+01
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; CHECK-NEXT: ret float [[TMP2]]
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;
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%B = fmul reassoc nsz float %X1, 47. ; X1*47
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%C = fmul reassoc nsz float %X2, -47. ; X2*-47
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%D = fadd reassoc nsz float %B, %C ; X1*47 + X2*-47 -> 47*(X1-X2)
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ret float %D
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}
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; TODO: This doesn't require 'nsz'. It should fold to ((x1 - x2) * 47.0)
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define float @test13_reassoc(float %X1, float %X2) {
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; CHECK-LABEL: @test13_reassoc(
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; CHECK-NEXT: [[B:%.*]] = fmul reassoc float [[X1:%.*]], 4.700000e+01
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; CHECK-NEXT: [[C:%.*]] = fmul reassoc float [[X2:%.*]], 4.700000e+01
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; CHECK-NEXT: [[TMP1:%.*]] = fsub reassoc float [[B]], [[C]]
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; CHECK-NEXT: ret float [[TMP1]]
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;
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%B = fmul reassoc float %X1, 47. ; X1*47
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%C = fmul reassoc float %X2, -47. ; X2*-47
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%D = fadd reassoc float %B, %C ; X1*47 + X2*-47 -> 47*(X1-X2)
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ret float %D
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}
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; (b+(a+1234))+-a -> b+1234
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define float @test15(float %b, float %a) {
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; CHECK-LABEL: @test15(
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; CHECK-NEXT: [[TMP1:%.*]] = fadd fast float [[B:%.*]], 1.234000e+03
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; CHECK-NEXT: ret float [[TMP1]]
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;
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%1 = fadd fast float %a, 1234.0
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%2 = fadd fast float %b, %1
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%3 = fsub fast float 0.0, %a
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%4 = fadd fast float %2, %3
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ret float %4
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}
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define float @test15_unary_fneg(float %b, float %a) {
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; CHECK-LABEL: @test15_unary_fneg(
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; CHECK-NEXT: [[TMP1:%.*]] = fadd fast float [[B:%.*]], 1.234000e+03
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; CHECK-NEXT: ret float [[TMP1]]
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;
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%1 = fadd fast float %a, 1234.0
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%2 = fadd fast float %b, %1
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%3 = fneg fast float %a
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%4 = fadd fast float %2, %3
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ret float %4
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}
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define float @test15_reassoc_nsz(float %b, float %a) {
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; CHECK-LABEL: @test15_reassoc_nsz(
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; CHECK-NEXT: [[TMP1:%.*]] = fadd reassoc nsz float [[B:%.*]], 1.234000e+03
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; CHECK-NEXT: ret float [[TMP1]]
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;
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%1 = fadd reassoc nsz float %a, 1234.0
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%2 = fadd reassoc nsz float %b, %1
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%3 = fsub reassoc nsz float 0.0, %a
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%4 = fadd reassoc nsz float %2, %3
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ret float %4
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}
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define float @test15_reassoc(float %b, float %a) {
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; CHECK-LABEL: @test15_reassoc(
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; CHECK-NEXT: [[TMP1:%.*]] = fadd reassoc float [[A:%.*]], 1.234000e+03
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; CHECK-NEXT: [[TMP2:%.*]] = fadd reassoc float [[B:%.*]], [[TMP1]]
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; CHECK-NEXT: [[TMP3:%.*]] = fsub reassoc float 0.000000e+00, [[A]]
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; CHECK-NEXT: [[TMP4:%.*]] = fadd reassoc float [[TMP3]], [[TMP2]]
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; CHECK-NEXT: ret float [[TMP4]]
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;
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%1 = fadd reassoc float %a, 1234.0
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%2 = fadd reassoc float %b, %1
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%3 = fsub reassoc float 0.0, %a
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%4 = fadd reassoc float %2, %3
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ret float %4
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}
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; Test that we can turn things like X*-(Y*Z) -> X*-1*Y*Z.
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define float @test16(float %a, float %b, float %z) {
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; REASSOC_AND_IC-LABEL: @test16(
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; REASSOC_AND_IC-NEXT: [[C:%.*]] = fmul fast float [[A:%.*]], 1.234500e+04
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; REASSOC_AND_IC-NEXT: [[E:%.*]] = fmul fast float [[C]], [[B:%.*]]
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; REASSOC_AND_IC-NEXT: [[F:%.*]] = fmul fast float [[E]], [[Z:%.*]]
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; REASSOC_AND_IC-NEXT: ret float [[F]]
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;
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; O2-LABEL: @test16(
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; O2-NEXT: [[D:%.*]] = fmul fast float [[A:%.*]], 1.234500e+04
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; O2-NEXT: [[E:%.*]] = fmul fast float [[D]], [[B:%.*]]
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; O2-NEXT: [[G:%.*]] = fmul fast float [[E]], [[Z:%.*]]
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; O2-NEXT: ret float [[G]]
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;
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%c = fsub fast float 0.000000e+00, %z
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%d = fmul fast float %a, %b
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%e = fmul fast float %c, %d
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%f = fmul fast float %e, 1.234500e+04
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%g = fsub fast float 0.000000e+00, %f
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ret float %g
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}
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define float @test16_unary_fneg(float %a, float %b, float %z) {
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; REASSOC_AND_IC-LABEL: @test16_unary_fneg(
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; REASSOC_AND_IC-NEXT: [[E:%.*]] = fmul fast float [[A:%.*]], 1.234500e+04
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; REASSOC_AND_IC-NEXT: [[F:%.*]] = fmul fast float [[E]], [[B:%.*]]
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; REASSOC_AND_IC-NEXT: [[G:%.*]] = fmul fast float [[F]], [[Z:%.*]]
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; REASSOC_AND_IC-NEXT: ret float [[G]]
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;
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; O2-LABEL: @test16_unary_fneg(
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; O2-NEXT: [[D:%.*]] = fmul fast float [[A:%.*]], 1.234500e+04
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; O2-NEXT: [[E:%.*]] = fmul fast float [[D]], [[B:%.*]]
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; O2-NEXT: [[G:%.*]] = fmul fast float [[E]], [[Z:%.*]]
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; O2-NEXT: ret float [[G]]
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;
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%c = fneg fast float %z
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%d = fmul fast float %a, %b
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%e = fmul fast float %c, %d
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%f = fmul fast float %e, 1.234500e+04
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%g = fneg fast float %f
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ret float %g
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}
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define float @test16_reassoc_nsz(float %a, float %b, float %z) {
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; REASSOC_AND_IC-LABEL: @test16_reassoc_nsz(
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; REASSOC_AND_IC-NEXT: [[C:%.*]] = fmul reassoc nsz float [[A:%.*]], 1.234500e+04
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; REASSOC_AND_IC-NEXT: [[E:%.*]] = fmul reassoc nsz float [[C]], [[B:%.*]]
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; REASSOC_AND_IC-NEXT: [[F:%.*]] = fmul reassoc nsz float [[E]], [[Z:%.*]]
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; REASSOC_AND_IC-NEXT: ret float [[F]]
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;
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; O2-LABEL: @test16_reassoc_nsz(
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; O2-NEXT: [[D:%.*]] = fmul reassoc nsz float [[A:%.*]], 1.234500e+04
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; O2-NEXT: [[E:%.*]] = fmul reassoc nsz float [[D]], [[B:%.*]]
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; O2-NEXT: [[G:%.*]] = fmul reassoc nsz float [[E]], [[Z:%.*]]
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; O2-NEXT: ret float [[G]]
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;
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%c = fsub reassoc nsz float 0.000000e+00, %z
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%d = fmul reassoc nsz float %a, %b
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%e = fmul reassoc nsz float %c, %d
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%f = fmul reassoc nsz float %e, 1.234500e+04
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%g = fsub reassoc nsz float 0.000000e+00, %f
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ret float %g
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}
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define float @test16_reassoc(float %a, float %b, float %z) {
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; CHECK-LABEL: @test16_reassoc(
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; CHECK-NEXT: [[C:%.*]] = fsub reassoc float 0.000000e+00, [[Z:%.*]]
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; CHECK-NEXT: [[D:%.*]] = fmul reassoc float [[A:%.*]], [[B:%.*]]
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; CHECK-NEXT: [[E:%.*]] = fmul reassoc float [[D]], [[C]]
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; CHECK-NEXT: [[F:%.*]] = fmul reassoc float [[E]], 1.234500e+04
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; CHECK-NEXT: [[G:%.*]] = fsub reassoc float 0.000000e+00, [[F]]
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; CHECK-NEXT: ret float [[G]]
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;
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%c = fsub reassoc float 0.000000e+00, %z
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%d = fmul reassoc float %a, %b
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%e = fmul reassoc float %c, %d
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%f = fmul reassoc float %e, 1.234500e+04
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%g = fsub reassoc float 0.000000e+00, %f
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ret float %g
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}
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; With sub reassociation, constant folding can eliminate the 12 and -12 constants.
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define float @test18(float %A, float %B) {
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; CHECK-LABEL: @test18(
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; CHECK-NEXT: [[Z:%.*]] = fsub fast float [[A:%.*]], [[B:%.*]]
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; CHECK-NEXT: ret float [[Z]]
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;
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%X = fadd fast float -1.200000e+01, %A
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%Y = fsub fast float %X, %B
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%Z = fadd fast float %Y, 1.200000e+01
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ret float %Z
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}
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define float @test18_reassoc(float %A, float %B) {
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; CHECK-LABEL: @test18_reassoc(
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; CHECK-NEXT: [[X:%.*]] = fadd reassoc float [[A:%.*]], -1.200000e+01
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; CHECK-NEXT: [[Y:%.*]] = fsub reassoc float [[X]], [[B:%.*]]
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; CHECK-NEXT: [[Z:%.*]] = fadd reassoc float [[Y]], 1.200000e+01
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; CHECK-NEXT: ret float [[Z]]
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;
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%X = fadd reassoc float -1.200000e+01, %A
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%Y = fsub reassoc float %X, %B
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%Z = fadd reassoc float %Y, 1.200000e+01
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ret float %Z
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}
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; test18 - check that the bug described in the revision does not appear:
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; https://reviews.llvm.org/D72521
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; With sub reassociation, constant folding can eliminate the uses of %a.
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define float @test19(float %a, float %b, float %c) nounwind {
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; REASSOC_AND_IC-LABEL: @test19(
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; REASSOC_AND_IC-NEXT: [[TMP1:%.*]] = fadd fast float [[B:%.*]], [[C:%.*]]
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; REASSOC_AND_IC-NEXT: [[T7:%.*]] = fneg fast float [[TMP1]]
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; REASSOC_AND_IC-NEXT: ret float [[T7]]
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;
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; O2-LABEL: @test19(
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; O2-NEXT: [[TMP1:%.*]] = fadd fast float [[C:%.*]], [[B:%.*]]
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; O2-NEXT: [[T7:%.*]] = fneg fast float [[TMP1]]
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; O2-NEXT: ret float [[T7]]
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;
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%t3 = fsub fast float %a, %b
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%t5 = fsub fast float %t3, %c
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%t7 = fsub fast float %t5, %a
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ret float %t7
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}
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define float @test19_reassoc_nsz(float %a, float %b, float %c) nounwind {
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; REASSOC_AND_IC-LABEL: @test19_reassoc_nsz(
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; REASSOC_AND_IC-NEXT: [[TMP1:%.*]] = fadd reassoc nsz float [[B:%.*]], [[C:%.*]]
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; REASSOC_AND_IC-NEXT: [[T7:%.*]] = fneg reassoc nsz float [[TMP1]]
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; REASSOC_AND_IC-NEXT: ret float [[T7]]
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;
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; O2-LABEL: @test19_reassoc_nsz(
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; O2-NEXT: [[TMP1:%.*]] = fadd reassoc nsz float [[C:%.*]], [[B:%.*]]
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; O2-NEXT: [[T7:%.*]] = fneg reassoc nsz float [[TMP1]]
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; O2-NEXT: ret float [[T7]]
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;
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%t3 = fsub reassoc nsz float %a, %b
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%t5 = fsub reassoc nsz float %t3, %c
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%t7 = fsub reassoc nsz float %t5, %a
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ret float %t7
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}
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; Verify the fold is not done with only 'reassoc' ('nsz' is required).
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define float @test19_reassoc(float %a, float %b, float %c) nounwind {
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; CHECK-LABEL: @test19_reassoc(
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; CHECK-NEXT: [[T3:%.*]] = fsub reassoc float [[A:%.*]], [[B:%.*]]
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; CHECK-NEXT: [[T5:%.*]] = fsub reassoc float [[T3]], [[C:%.*]]
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; CHECK-NEXT: [[T7:%.*]] = fsub reassoc float [[T5]], [[A]]
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; CHECK-NEXT: ret float [[T7]]
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;
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%t3 = fsub reassoc float %a, %b
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%t5 = fsub reassoc float %t3, %c
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%t7 = fsub reassoc float %t5, %a
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ret float %t7
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}
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