From e7c94ef1debe790ab90833cf72e21b584651db16 Mon Sep 17 00:00:00 2001 From: Sanjay Patel Date: Sun, 4 Nov 2018 14:28:48 +0000 Subject: [ValueTracking] determine sign of 0.0 from select when matching min/max FP In PR39475: https://bugs.llvm.org/show_bug.cgi?id=39475 ..we may fail to recognize/simplify fabs() in some cases because we do not canonicalize fcmp with a -0.0 operand. Adding that canonicalization can cause regressions on min/max FP tests, so that's this patch: for the purpose of determining whether something is min/max, let the value returned by the select determine how we treat a 0.0 operand in the fcmp. This patch doesn't actually change the -0.0 to +0.0. It just changes the analysis, so we don't fail to recognize equivalent min/max patterns that only differ in the signbit of 0.0. Differential Revision: https://reviews.llvm.org/D54001 llvm-svn: 346097 --- llvm/unittests/Analysis/ValueTrackingTest.cpp | 84 +++++++++++++++++---------- 1 file changed, 53 insertions(+), 31 deletions(-) (limited to 'llvm/unittests/Analysis/ValueTrackingTest.cpp') diff --git a/llvm/unittests/Analysis/ValueTrackingTest.cpp b/llvm/unittests/Analysis/ValueTrackingTest.cpp index b13948adad7..c4adde4abe3 100644 --- a/llvm/unittests/Analysis/ValueTrackingTest.cpp +++ b/llvm/unittests/Analysis/ValueTrackingTest.cpp @@ -156,8 +156,8 @@ TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero1) { " %A = select i1 %1, float 0.0, float %a\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMINNUM, SPNB_RETURNS_NAN, true}); } TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero2) { @@ -167,8 +167,8 @@ TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero2) { " %A = select i1 %1, float 0.0, float %a\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMINNUM, SPNB_RETURNS_NAN, false}); } TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero3) { @@ -178,8 +178,8 @@ TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero3) { " %A = select i1 %1, float -0.0, float %a\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMINNUM, SPNB_RETURNS_NAN, true}); } TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero4) { @@ -189,8 +189,8 @@ TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero4) { " %A = select i1 %1, float -0.0, float %a\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMINNUM, SPNB_RETURNS_NAN, false}); } TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero5) { @@ -200,8 +200,8 @@ TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero5) { " %A = select i1 %1, float %a, float 0.0\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMINNUM, SPNB_RETURNS_OTHER, false}); } TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero6) { @@ -211,8 +211,8 @@ TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero6) { " %A = select i1 %1, float %a, float 0.0\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMINNUM, SPNB_RETURNS_OTHER, true}); } TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero7) { @@ -222,8 +222,8 @@ TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero7) { " %A = select i1 %1, float %a, float -0.0\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMINNUM, SPNB_RETURNS_OTHER, false}); } TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero8) { @@ -233,8 +233,8 @@ TEST_F(MatchSelectPatternTest, FMinMismatchConstantZero8) { " %A = select i1 %1, float %a, float -0.0\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMINNUM, SPNB_RETURNS_OTHER, true}); } TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero1) { @@ -244,8 +244,8 @@ TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero1) { " %A = select i1 %1, float 0.0, float %a\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMAXNUM, SPNB_RETURNS_NAN, true}); } TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero2) { @@ -255,8 +255,8 @@ TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero2) { " %A = select i1 %1, float 0.0, float %a\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMAXNUM, SPNB_RETURNS_NAN, false}); } TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero3) { @@ -266,8 +266,8 @@ TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero3) { " %A = select i1 %1, float -0.0, float %a\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMAXNUM, SPNB_RETURNS_NAN, true}); } TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero4) { @@ -277,8 +277,8 @@ TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero4) { " %A = select i1 %1, float -0.0, float %a\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMAXNUM, SPNB_RETURNS_NAN, false}); } TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero5) { @@ -288,8 +288,8 @@ TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero5) { " %A = select i1 %1, float %a, float 0.0\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMAXNUM, SPNB_RETURNS_OTHER, false}); } TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero6) { @@ -299,8 +299,8 @@ TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero6) { " %A = select i1 %1, float %a, float 0.0\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMAXNUM, SPNB_RETURNS_OTHER, true}); } TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero7) { @@ -310,8 +310,8 @@ TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero7) { " %A = select i1 %1, float %a, float -0.0\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. - expectPattern({SPF_UNKNOWN, SPNB_NA, false}); + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMAXNUM, SPNB_RETURNS_OTHER, false}); } TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero8) { @@ -321,7 +321,29 @@ TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZero8) { " %A = select i1 %1, float %a, float -0.0\n" " ret float %A\n" "}\n"); - // FIXME: The sign of zero doesn't matter in fcmp. + // The sign of zero doesn't matter in fcmp. + expectPattern({SPF_FMAXNUM, SPNB_RETURNS_OTHER, true}); +} + +TEST_F(MatchSelectPatternTest, FMinMismatchConstantZeroVecUndef) { + parseAssembly( + "define <2 x float> @test(<2 x float> %a) {\n" + " %1 = fcmp ogt <2 x float> %a, \n" + " %A = select <2 x i1> %1, <2 x float> , <2 x float> %a\n" + " ret <2 x float> %A\n" + "}\n"); + // An undef in a vector constant can not be back-propagated for this analysis. + expectPattern({SPF_UNKNOWN, SPNB_NA, false}); +} + +TEST_F(MatchSelectPatternTest, FMaxMismatchConstantZeroVecUndef) { + parseAssembly( + "define <2 x float> @test(<2 x float> %a) {\n" + " %1 = fcmp ogt <2 x float> %a, zeroinitializer\n" + " %A = select <2 x i1> %1, <2 x float> %a, <2 x float> \n" + " ret <2 x float> %A\n" + "}\n"); + // An undef in a vector constant can not be back-propagated for this analysis. expectPattern({SPF_UNKNOWN, SPNB_NA, false}); } -- cgit v1.2.3