[llvm] Optimize fptrunc(x)>=C1 --> x>=C2 (PR #99475)

[Matt Arsenault via llvm-commits]

================
@@ -1,11 +1,125 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
 ; RUN: opt -passes=instcombine -S < %s | FileCheck %s
 
 
-;CHECK-LABEL: @src(
-;CHECK: %result = fcmp oge double %0, 1.000000e+02
-;CHECK-NEXT: ret i1 %result
-define i1 @src(double %0) {
-    %trunc = fptrunc double %0 to float
-    %result = fcmp oge float %trunc, 1.000000e+02
-    ret i1 %result
-}
\ No newline at end of file
+define i1 @fcmp_trunc(double %0) {
+; CHECK-LABEL: define i1 @fcmp_trunc(
+; CHECK-SAME: double [[TMP0:%.*]]) {
+; CHECK-NEXT:    [[RESULT:%.*]] = fcmp oge double [[TMP0]], 1.000000e+02
+; CHECK-NEXT:    ret i1 [[RESULT]]
+;
+  %trunc = fptrunc double %0 to float
+  %result = fcmp oge float %trunc, 1.000000e+02
+  ret i1 %result
+}
+
+define i1 @fcmp_trunc_with_nnan(double %0) {
+; CHECK-LABEL: define i1 @fcmp_trunc_with_nnan(
+; CHECK-SAME: double [[TMP0:%.*]]) {
+; CHECK-NEXT:    [[RESULT:%.*]] = fcmp nnan oge double [[TMP0]], 1.000000e+02
+; CHECK-NEXT:    ret i1 [[RESULT]]
+;
+  %trunc = fptrunc double %0 to float
+  %result = fcmp nnan oge float %trunc, 1.000000e+02
+  ret i1 %result
+}
+
+define i1 @fcmp_trunc_with_ninf(double %0) {
+; CHECK-LABEL: define i1 @fcmp_trunc_with_ninf(
+; CHECK-SAME: double [[TMP0:%.*]]) {
+; CHECK-NEXT:    [[RESULT:%.*]] = fcmp ninf oge double [[TMP0]], 1.000000e+02
+; CHECK-NEXT:    ret i1 [[RESULT]]
+;
+  %trunc = fptrunc double %0 to float
+  %result = fcmp ninf oge float %trunc, 1.000000e+02
+  ret i1 %result
+}
+
+define i1 @fcmp_trunc_with_nsz(double %0) {
+; CHECK-LABEL: define i1 @fcmp_trunc_with_nsz(
+; CHECK-SAME: double [[TMP0:%.*]]) {
+; CHECK-NEXT:    [[RESULT:%.*]] = fcmp nsz oge double [[TMP0]], 1.000000e+02
+; CHECK-NEXT:    ret i1 [[RESULT]]
+;
+  %trunc = fptrunc double %0 to float
+  %result = fcmp nsz oge float %trunc, 1.000000e+02
+  ret i1 %result
+}
+
+define i1 @fcmp_trunc_with_reassoc(double %0) {
+; CHECK-LABEL: define i1 @fcmp_trunc_with_reassoc(
+; CHECK-SAME: double [[TMP0:%.*]]) {
+; CHECK-NEXT:    [[RESULT:%.*]] = fcmp reassoc oge double [[TMP0]], 1.000000e+02
+; CHECK-NEXT:    ret i1 [[RESULT]]
+;
+  %trunc = fptrunc double %0 to float
+  %result = fcmp reassoc oge float %trunc, 1.000000e+02
+  ret i1 %result
+}
+
+define i1 @fcmp_trunc_with_fast(double %0) {
+; CHECK-LABEL: define i1 @fcmp_trunc_with_fast(
+; CHECK-SAME: double [[TMP0:%.*]]) {
+; CHECK-NEXT:    [[RESULT:%.*]] = fcmp fast oge double [[TMP0]], 1.000000e+02
+; CHECK-NEXT:    ret i1 [[RESULT]]
+;
+  %trunc = fptrunc double %0 to float
+  %result = fcmp fast oge float %trunc, 1.000000e+02
+  ret i1 %result
+}
+
+define <4 x i1> @fcmp_vec_trunc(<4 x double> %0) {
+; CHECK-LABEL: define <4 x i1> @fcmp_vec_trunc(
+; CHECK-SAME: <4 x double> [[TMP0:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp olt <4 x double> [[TMP0]], <double 1.000000e+00, double 2.000000e+00, double 3.000000e+00, double 4.000000e+00>
+; CHECK-NEXT:    ret <4 x i1> [[CMP]]
+;
+  %vec = fptrunc <4 x double> %0 to <4 x float>
+  %cmp = fcmp olt <4 x float> %vec, <float 1.0, float 2.0, float 3.0, float 4.0>
+  ret <4 x i1> %cmp
+}
+
+define <4 x i1> @fcmp_vec_trunc_with_flag(<4 x double> %0) {
+; CHECK-LABEL: define <4 x i1> @fcmp_vec_trunc_with_flag(
+; CHECK-SAME: <4 x double> [[TMP0:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp fast olt <4 x double> [[TMP0]], <double 1.000000e+00, double 2.000000e+00, double 3.000000e+00, double 4.000000e+00>
+; CHECK-NEXT:    ret <4 x i1> [[CMP]]
+;
+  %vec = fptrunc <4 x double> %0 to <4 x float>
+  %cmp = fcmp fast olt <4 x float> %vec, <float 1.0, float 2.0, float 3.0, float 4.0>
+  ret <4 x i1> %cmp
+}
+
----------------
arsenm wrote:

Add a scalable vector test 

https://github.com/llvm/llvm-project/pull/99475