[ValueTracking] Add additional tests for llvm.powi. NFC.

Author: dtcxzyw

llvm/test/Analysis/ValueTracking/powi-nneg.ll

@@ -0,0 +1,51 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -passes=instsimplify -S < %s | FileCheck %s
+
+define i1 @test_powi_even_exp(float %x) {
+; CHECK-LABEL: define i1 @test_powi_even_exp(
+; CHECK-SAME: float [[X:%.*]]) {
+; CHECK-NEXT:    ret i1 false
+;
+  %y = call float @llvm.powi.f32(float %x, i32 8)
+  %cmp = fcmp olt float %y, 0.0
+  ret i1 %cmp
+}
+
+define i1 @test_powi_base(float nofpclass(ninf nnorm nsub nzero) %x, i32 %e) {
+; CHECK-LABEL: define i1 @test_powi_base(
+; CHECK-SAME: float nofpclass(ninf nzero nsub nnorm) [[X:%.*]], i32 [[E:%.*]]) {
+; CHECK-NEXT:    ret i1 false
+;
+  %y = call float @llvm.powi.f32(float %x, i32 %e)
+  %cmp = fcmp olt float %y, 0.0
+  ret i1 %cmp
+}
+
+define i1 @test_powi_base_without_nsz(float nofpclass(ninf nnorm nsub) %x, i32 %e) {
+; CHECK-LABEL: define i1 @test_powi_base_without_nsz(
+; CHECK-SAME: float nofpclass(ninf nsub nnorm) [[X:%.*]], i32 [[E:%.*]]) {
+; CHECK-NEXT:    [[Y:%.*]] = call float @llvm.powi.f32.i32(float [[X]], i32 [[E]])
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp olt float [[Y]], 0.000000e+00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %y = call float @llvm.powi.f32(float %x, i32 %e)
+  %cmp = fcmp olt float %y, 0.0
+  ret i1 %cmp
+}
+
+define float @pr31702(float %x, i32 %n) {
+; CHECK-LABEL: define float @pr31702(
+; CHECK-SAME: float [[X:%.*]], i32 [[N:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CALL1:%.*]] = call float @llvm.powi.f32.i32(float -0.000000e+00, i32 [[N]])
+; CHECK-NEXT:    [[CALL2:%.*]] = call float @llvm.fabs.f32(float [[CALL1]])
+; CHECK-NEXT:    ret float [[CALL2]]
+;
+entry:
+  %call1 = call float @llvm.powi.f32(float -0.0, i32 %n)
+  %call2 = call float @llvm.fabs.f32(float %call1)
+  ret float %call2
+}
+
+declare float @llvm.powi.f32(float, i32)
+declare float @llvm.fabs.f32(float)