[llvm] [AggressiveInstCombine] Inline strcmp/strncmp (PR #89371)

[via llvm-commits]

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@@ -0,0 +1,165 @@
+; RUN: opt -S -passes=aggressive-instcombine -strncmp-inline-threshold=3 < %s | FileCheck %s
+
+declare i32 @strncmp(ptr nocapture, ptr nocapture, i64)
+declare i32 @strcmp(ptr nocapture, ptr nocapture)
+
+ at .str = private unnamed_addr constant [3 x i8] c"aa\00", align 1
+ at .str.1 = private unnamed_addr constant [4 x i8] c"aab\00", align 1
+ at __const.test_strncmp_8.s2 = private unnamed_addr constant [2 x i8] c"aa", align 1
+
+; int test_strncmp_1(const char *s) {
+;   if (!strncmp(s, "aa", 2))
+;     return 11;
+;   return 41;
+; }
+define i32 @test_strncmp_1(i8* nocapture readonly %s) {
+entry:
+  %call = tail call i32 @strncmp(ptr nonnull dereferenceable(1) %s, ptr nonnull dereferenceable(3) @.str, i64 2)
+  %tobool.not = icmp eq i32 %call, 0
+  %retval.0 = select i1 %tobool.not, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strncmp_1(
+; CHECK-NOT: @strncmp
+
+define i32 @test_strncmp_1_dereferenceable(i8* nocapture readonly dereferenceable(2) %s) {
+entry:
+  %call = tail call i32 @strncmp(ptr nonnull %s, ptr nonnull dereferenceable(3) @.str, i64 2)
+  %tobool.not = icmp eq i32 %call, 0
+  %retval.0 = select i1 %tobool.not, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strncmp_1_dereferenceable(
+; CHECK: @strncmp
+
+; int test_strncmp_2(const char *s) {
+;   if (!strncmp(s, "aa", 3))
+;     return 11;
+;   return 41;
+; }
+define i32 @test_strncmp_2(i8* nocapture readonly %s) {
+entry:
+  %call = tail call i32 @strncmp(ptr nonnull dereferenceable(1) %s, ptr nonnull dereferenceable(3) @.str, i64 3)
+  %tobool.not = icmp eq i32 %call, 0
+  %retval.0 = select i1 %tobool.not, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strncmp_2(
+; CHECK-NOT: @strncmp
+
+; int test_strncmp_3(const char *s) {
+;   if (!strncmp(s, "aab", 3))
+;     return 11;
+;   return 41;
+; }
+define i32 @test_strncmp_3(i8* nocapture readonly %s) {
+entry:
+  %call = tail call i32 @strncmp(ptr nonnull dereferenceable(1) %s, ptr nonnull dereferenceable(4) @.str.1, i64 3)
+  %tobool.not = icmp eq i32 %call, 0
+  %retval.0 = select i1 %tobool.not, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strncmp_3(
+; CHECK-NOT: @strncmp
+
+; int test_strncmp_4(const char *s) {
+;   if (!strncmp(s, "aab", 4))
+;     return 11;
+;   return 41;
+; }
+define i32 @test_strncmp_4(i8* nocapture readonly %s) {
+entry:
+  %call = tail call i32 @strncmp(ptr nonnull dereferenceable(1) %s, ptr nonnull dereferenceable(4) @.str.1, i64 4)
+  %tobool.not = icmp eq i32 %call, 0
+  %retval.0 = select i1 %tobool.not, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strncmp_4(
+; CHECK: @strncmp
+
+; int test_strncmp_5(const char *s) {
+;   if (strncmp(s, "aa", 2) < 0)
+;     return 11;
+;   return 41;
+; }
+define i32 @test_strncmp_5(i8* nocapture readonly %s) {
+entry:
+  %call = tail call i32 @strncmp(ptr nonnull dereferenceable(1) %s, ptr nonnull dereferenceable(3) @.str, i64 2)
+  %cmp = icmp slt i32 %call, 0
+  %retval.0 = select i1 %cmp, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strncmp_5(
+; CHECK-NOT: @strncmp
+
+; int test_strncmp_6(const char *s1) {
+;   char s2[] = {'a', 'a'};
+;   if (strncmp(s1, s2, 2) < 0)
+;     return 11;
+;   return 41;
+; }
+define i32 @test_strncmp_6(i8* nocapture readonly %s1) {
+entry:
+  %call = tail call i32 @strncmp(ptr nonnull dereferenceable(1) %s1, ptr nonnull dereferenceable(3) @__const.test_strncmp_8.s2, i64 2)
+  %cmp = icmp slt i32 %call, 0
+  %retval.0 = select i1 %cmp, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strncmp_6(
+; CHECK-NOT: @strncmp
+
+; int test_strncmp_7(const char *s1) {
+;   char s2[] = {'a', 'a'};
+;   if (strncmp(s1, s2, 3) < 0)
+;     return 11;
+;   return 41;
+; }
+define i32 @test_strncmp_7(i8* nocapture readonly %s1) {
+entry:
+  %call = tail call i32 @strncmp(ptr nonnull dereferenceable(1) %s1, ptr nonnull dereferenceable(3) @__const.test_strncmp_8.s2, i64 3)
+  %cmp = icmp slt i32 %call, 0
+  %retval.0 = select i1 %cmp, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strncmp_7(
+; CHECK: @strncmp
+
+; int test_strcmp_1(const char *s) {
+;   if (!strcmp(s, "aa"))
+;     return 11;
+;   return 41;
+; }
+define i32 @test_strcmp_1(i8* nocapture readonly %s) {
+entry:
+  %call = tail call i32 @strcmp(ptr nonnull dereferenceable(1) %s, ptr nonnull dereferenceable(3) @.str)
+  %tobool.not = icmp eq i32 %call, 0
+  %retval.0 = select i1 %tobool.not, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strcmp_1(
+; CHECK-NOT: @strcmp
+
+define i32 @test_strcmp_1_dereferenceable(i8* nocapture readonly dereferenceable(2) %s) {
+entry:
+  %call = tail call i32 @strcmp(ptr nonnull %s, ptr nonnull dereferenceable(3) @.str)
+  %tobool.not = icmp eq i32 %call, 0
+  %retval.0 = select i1 %tobool.not, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strcmp_1_dereferenceable(
+; CHECK: @strcmp
+
+; int test_strcmp_2(const char *s) {
+;   if (!strcmp(s, "aab"))
+;     return 11;
+;   return 41;
+; }
+define i32 @test_strcmp_2(i8* nocapture readonly %s) {
+entry:
+  %call = tail call i32 @strcmp(ptr nonnull dereferenceable(1) %s, ptr nonnull dereferenceable(4) @.str.1)
+  %tobool.not = icmp eq i32 %call, 0
+  %retval.0 = select i1 %tobool.not, i32 11, i32 41
+  ret i32 %retval.0
+}
+; CHECK-LABEL: @test_strcmp_2(
+; CHECK: @strcmp
----------------
goldsteinn wrote:

I think some tests w/ a threshold of 1/2/4 would be good.

https://github.com/llvm/llvm-project/pull/89371