[X86] Remove an unnecessary 'if' that prevented treating INT64_MAX and -INT64_MAX as power of 2 minus 1 in the multiply expansion code.

Not sure why they were being explicitly excluded, but I believe all the math inside the if works. I changed the absolute value to be uint64_t instead of int64_t so INT64_MIN+1 wouldn't be signed wrap.

llvm-svn: 338101

1 files changed, 27 insertions, 2 deletions

diff --git a/llvm/test/CodeGen/X86/imul.ll b/llvm/test/CodeGen/X86/imul.ll
index 14f15143b95..0f1a824f00f 100644
--- a/llvm/test/CodeGen/X86/imul.ll
+++ b/llvm/test/CodeGen/X86/imul.ll
@@ -499,8 +499,9 @@ entry:
 define i64 @testOverflow(i64 %a) {
 ; X64-LABEL: testOverflow:
 ; X64:       # %bb.0: # %entry
-; X64-NEXT:    movabsq $9223372036854775807, %rax # imm = 0x7FFFFFFFFFFFFFFF
-; X64-NEXT:    imulq %rdi, %rax
+; X64-NEXT:    movq %rdi, %rax
+; X64-NEXT:    shlq $63, %rax
+; X64-NEXT:    subq %rdi, %rax
 ; X64-NEXT:    retq
 ;
 ; X86-LABEL: testOverflow:
@@ -524,3 +525,27 @@ entry:
 	%tmp3 = mul i64 %a, 9223372036854775807
 	ret i64 %tmp3
 }
+
+define i64 @testNegOverflow(i64 %a) {
+; X64-LABEL: testNegOverflow:
+; X64:       # %bb.0: # %entry
+; X64-NEXT:    movq %rdi, %rax
+; X64-NEXT:    shlq $63, %rax
+; X64-NEXT:    subq %rax, %rdi
+; X64-NEXT:    movq %rdi, %rax
+; X64-NEXT:    retq
+;
+; X86-LABEL: testNegOverflow:
+; X86:       # %bb.0: # %entry
+; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X86-NEXT:    movl $1, %edx
+; X86-NEXT:    movl %ecx, %eax
+; X86-NEXT:    mull %edx
+; X86-NEXT:    shll $31, %ecx
+; X86-NEXT:    addl %ecx, %edx
+; X86-NEXT:    addl {{[0-9]+}}(%esp), %edx
+; X86-NEXT:    retl
+entry:
+	%tmp3 = mul i64 %a, -9223372036854775807
+	ret i64 %tmp3
+}