[llvm] [InstCombine] Canonicalize fcmp with inf (PR #80986)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,200 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+
+define i1 @olt_pinf(half %x) {
+; CHECK-LABEL: define i1 @olt_pinf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp one half [[X]], 0xH7C00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp olt half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+define i1 @ole_pinf(half %x) {
+; CHECK-LABEL: define i1 @ole_pinf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp ord half [[X]], 0xH0000
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp ole half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+define i1 @ogt_pinf(half %x) {
+; CHECK-LABEL: define i1 @ogt_pinf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    ret i1 false
+;
+  %cmp = fcmp ogt half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+define i1 @oge_pinf(half %x) {
+; CHECK-LABEL: define i1 @oge_pinf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp oeq half [[X]], 0xH7C00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp oge half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+define i1 @ult_pinf(half %x) {
+; CHECK-LABEL: define i1 @ult_pinf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp une half [[X]], 0xH7C00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp ult half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+define i1 @ule_pinf(half %x) {
+; CHECK-LABEL: define i1 @ule_pinf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    ret i1 true
+;
+  %cmp = fcmp ule half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+define i1 @ugt_pinf(half %x) {
+; CHECK-LABEL: define i1 @ugt_pinf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp uno half [[X]], 0xH0000
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp ugt half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+define i1 @uge_pinf(half %x) {
+; CHECK-LABEL: define i1 @uge_pinf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp ueq half [[X]], 0xH7C00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp uge half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+define i1 @olt_ninf(half %x) {
+; CHECK-LABEL: define i1 @olt_ninf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    ret i1 false
+;
+  %cmp = fcmp olt half %x, 0xHfc00
+  ret i1 %cmp
+}
+
+define i1 @ole_ninf(half %x) {
+; CHECK-LABEL: define i1 @ole_ninf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp oeq half [[X]], 0xHFC00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp ole half %x, 0xHfc00
+  ret i1 %cmp
+}
+
+define i1 @ogt_ninf(half %x) {
+; CHECK-LABEL: define i1 @ogt_ninf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp one half [[X]], 0xHFC00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp ogt half %x, 0xHfc00
+  ret i1 %cmp
+}
+
+define i1 @oge_ninf(half %x) {
+; CHECK-LABEL: define i1 @oge_ninf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp ord half [[X]], 0xH0000
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp oge half %x, 0xHfc00
+  ret i1 %cmp
+}
+
+define i1 @ult_ninf(half %x) {
+; CHECK-LABEL: define i1 @ult_ninf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp uno half [[X]], 0xH0000
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp ult half %x, 0xHfc00
+  ret i1 %cmp
+}
+
+define i1 @ule_ninf(half %x) {
+; CHECK-LABEL: define i1 @ule_ninf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp ueq half [[X]], 0xHFC00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp ule half %x, 0xHfc00
+  ret i1 %cmp
+}
+
+define i1 @ugt_ninf(half %x) {
+; CHECK-LABEL: define i1 @ugt_ninf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp une half [[X]], 0xHFC00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp ugt half %x, 0xHfc00
+  ret i1 %cmp
+}
+
+define i1 @uge_ninf(half %x) {
+; CHECK-LABEL: define i1 @uge_ninf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    ret i1 true
+;
+  %cmp = fcmp uge half %x, 0xHfc00
+  ret i1 %cmp
+}
+
+define i1 @olt_pinf_fmf(half %x) {
+; CHECK-LABEL: define i1 @olt_pinf_fmf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp nsz one half [[X]], 0xH7C00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp nsz olt half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+define i1 @oge_pinf_fmf(half %x) {
+; CHECK-LABEL: define i1 @oge_pinf_fmf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp nnan oeq half [[X]], 0xH7C00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp nnan oge half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+; Negative tests
+
+define i1 @ord_pinf(half %x) {
+; CHECK-LABEL: define i1 @ord_pinf(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp ord half [[X]], 0xH0000
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp ord half %x, 0xH7c00
+  ret i1 %cmp
+}
+
+define i1 @olt_one(half %x) {
+; CHECK-LABEL: define i1 @olt_one(
+; CHECK-SAME: half [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp olt half [[X]], 0xH3C00
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %cmp = fcmp olt half %x, 1.0
+  ret i1 %cmp
+}
----------------
arsenm wrote:

test true / false for good measure. Also a few vector cases 

https://github.com/llvm/llvm-project/pull/80986