[ValueTracking] Allow select patterns to work on FP vectors

Summary:
This CL allows constant vectors of floats to be recognized as non-NaN
and non-zero in select patterns. This change makes
`matchSelectPattern` more powerful generally, but was motivated
specifically because I wanted fminnan and fmaxnan to be created for
vector versions of the scalar patterns they are created for.

Tested with check-all on all targets. A testcase in the WebAssembly
backend that tests the non-nan codepath is in an upcoming CL.

Reviewers: aheejin, dschuff

Subscribers: sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D52324

llvm-svn: 343364

1 files changed, 58 insertions, 0 deletions

diff --git a/llvm/unittests/Analysis/ValueTrackingTest.cpp b/llvm/unittests/Analysis/ValueTrackingTest.cpp
index cfdf264da31..f391ca12e55 100644
--- a/llvm/unittests/Analysis/ValueTrackingTest.cpp
+++ b/llvm/unittests/Analysis/ValueTrackingTest.cpp
@@ -149,6 +149,64 @@ TEST_F(MatchSelectPatternTest, FMinConstantZeroNsz) {
   expectPattern({SPF_FMINNUM, SPNB_RETURNS_OTHER, true});
 }
 
+TEST_F(MatchSelectPatternTest, VectorFMinNaN) {
+  parseAssembly(
+      "define <4 x float> @test(<4 x float> %a) {\n"
+      "  %1 = fcmp ule <4 x float> %a, \n"
+      "    <float 5.0, float 5.0, float 5.0, float 5.0>\n"
+      "  %A = select <4 x i1> %1, <4 x float> %a,\n"
+      "     <4 x float> <float 5.0, float 5.0, float 5.0, float 5.0>\n"
+      "  ret <4 x float> %A\n"
+      "}\n");
+  // Check that pattern matching works on vectors where each lane has the same
+  // unordered pattern.
+  expectPattern({SPF_FMINNUM, SPNB_RETURNS_NAN, false});
+}
+
+TEST_F(MatchSelectPatternTest, VectorFMinOtherOrdered) {
+  parseAssembly(
+      "define <4 x float> @test(<4 x float> %a) {\n"
+      "  %1 = fcmp ole <4 x float> %a, \n"
+      "    <float 5.0, float 5.0, float 5.0, float 5.0>\n"
+      "  %A = select <4 x i1> %1, <4 x float> %a,\n"
+      "     <4 x float> <float 5.0, float 5.0, float 5.0, float 5.0>\n"
+      "  ret <4 x float> %A\n"
+      "}\n");
+  // Check that pattern matching works on vectors where each lane has the same
+  // ordered pattern.
+  expectPattern({SPF_FMINNUM, SPNB_RETURNS_OTHER, true});
+}
+
+TEST_F(MatchSelectPatternTest, VectorNotFMinNaN) {
+  parseAssembly(
+      "define <4 x float> @test(<4 x float> %a) {\n"
+      "  %1 = fcmp ule <4 x float> %a, \n"
+      "    <float 5.0, float 0x7ff8000000000000, float 5.0, float 5.0>\n"
+      "  %A = select <4 x i1> %1, <4 x float> %a,\n"
+      "     <4 x float> <float 5.0, float 0x7ff8000000000000, float 5.0, float "
+      "5.0>\n"
+      "  ret <4 x float> %A\n"
+      "}\n");
+  // The lane that contains a NaN (0x7ff80...) behaves like a
+  // non-NaN-propagating min and the other lines behave like a NaN-propagating
+  // min, so check that neither is returned.
+  expectPattern({SPF_UNKNOWN, SPNB_NA, false});
+}
+
+TEST_F(MatchSelectPatternTest, VectorNotFMinZero) {
+  parseAssembly(
+      "define <4 x float> @test(<4 x float> %a) {\n"
+      "  %1 = fcmp ule <4 x float> %a, \n"
+      "    <float 5.0, float -0.0, float 5.0, float 5.0>\n"
+      "  %A = select <4 x i1> %1, <4 x float> %a,\n"
+      "     <4 x float> <float 5.0, float 0.0, float 5.0, float 5.0>\n"
+      "  ret <4 x float> %A\n"
+      "}\n");
+  // Always selects the second lane of %a if it is positive or negative zero, so
+  // this is stricter than a min.
+  expectPattern({SPF_UNKNOWN, SPNB_NA, false});
+}
+
 TEST_F(MatchSelectPatternTest, DoubleCastU) {
   parseAssembly(
       "define i32 @test(i8 %a, i8 %b) {\n"